Chromosome counts and speciation
Noelie S. Alito
Is there an extant species (sensu "interfertile in the wild") of
vertebrates where the chromosome count is not consistent
across all of the (fertile) members of the population, and
where individuals of differing chromosome counts mate
(i.e., produce offspring) indiscriminately?
Enquiring minds want to know!
Noelie
--
Waddaya get when you cross Lassie with a cantaloupe?
howard hershey
"Noelie S. Alito" wrote:
>
> Greetings,
>
> Is there an extant species (sensu "interfertile in the wild") of
> vertebrates where the chromosome count is not consistent
> across all of the (fertile) members of the population, and
> where individuals of differing chromosome counts mate
> (i.e., produce offspring) indiscriminately?
Yes. A number of insect species (and plants) have B or supernumery
chromosomes. Every species has some individuals with Robertsonian
translocations. These may (it depends) have a slightly reduced
fertility, but sometimes their fertility is indistinguishable from
normals. Other species have many small chromosomes, some of which can
be lost without affecting fertility (although they often have other
major to minor deleterious effects). Single chromosomal aberrations
such as ring, translocation, inversions that don't have a direct
phenotypic effect on the individual are generally insufficient to
prevent interfertility. Significant reduction in interfertility
usually requires a number of chromosome differences rather than simple
single differences.
Floyd
Noelie S. Alito <noe...@nospam.jump.net> wrote in article
<9bi0bm$313$1...@news.jump.net>...
> Greetings,
>
> Is there an extant species (sensu "interfertile in the wild") of
> vertebrates where the chromosome count is not consistent
> across all of the (fertile) members of the population, and
> where individuals of differing chromosome counts mate
> (i.e., produce offspring) indiscriminately?
>
> Enquiring minds want to know!
Some humans with trisomy 21 are fertile (I'm not sure, offhand, if their
children are also fertile, but I know they inherit the additional
chromosome). HTH
-Floyd
Noelie S. Alito
"howard hershey" <hers...@indiana.edu> wrote in message
news:3ADC9C32...@indiana.edu...
Well, I specifically wanted to know about vertebrates, where
if you grabbed a "normal-looking" you wouldn't know ahead
of time what the chromosome count would be.
What are Robertsonian translocations and don't they hurt?
Ken Cox
> What are Robertsonian translocations and don't they hurt?
http://gslc.genetics.utah.edu/disorders/karyotype/translocbkg.html
A form of chromosome fusion, two chromosomes become one,
with the loss of the short arms. The resulting mutant
may still be fertile, because the two chromosomes from
his/her mate can line up with her/his single one.
--
Ken Cox k...@research.bell-labs.com
mel turner
Alito] wrote...
>Greetings,
>
>Is there an extant species (sensu "interfertile in the wild") of
>vertebrates where the chromosome count is not consistent
>across all of the (fertile) members of the population, and
>where individuals of differing chromosome counts mate
>(i.e., produce offspring) indiscriminately?
>Enquiring minds want to know!
Short answer: sure. Lots.
Long answer is coming. I tried to find some older posts
with lots of refs [by Clark Dorman, myself and others],
but it looks like they're currently unavailable to
Google.
So, I went back to the Biological Abstracts database and
searched for "chromosom* and Robertsonian and polymorphi*"
and found too many. I'll tidy them up and post a bunch.
[See next post.]
>Noelie
>--
>Waddaya get when you cross Lassie with a cantaloupe?
A melon-collie baby.
cheers
Joseph Boxhorn
"Noelie S. Alito" wrote:
>
> Greetings,
>
> Is there an extant species (sensu "interfertile in the wild") of
> vertebrates where the chromosome count is not consistent
> across all of the (fertile) members of the population, and
> where individuals of differing chromosome counts mate
> (i.e., produce offspring) indiscriminately?
>
> Enquiring minds want to know!
>
> Noelie
>
A useful reference on this topic is:
King, M., 1993. Species evolution: The role of chromosome
change.
Cambridge University Press, Cambridge, UK.
Check the topic "balanced polymorphism.
========================================================
Joseph Boxhorn jbox...@execpc.com
"Coffee does not make you nervous. You own inadequacies
do that. Coffee just makes you aware of your
shortcomings." -- Dr. Science
========================================================
Joseph Boxhorn
"Noelie S. Alito" wrote:
>
> Greetings,
>
> Is there an extant species (sensu "interfertile in the wild") of
> vertebrates where the chromosome count is not consistent
> across all of the (fertile) members of the population, and
> where individuals of differing chromosome counts mate
> (i.e., produce offspring) indiscriminately?
>
> Enquiring minds want to know!
>
> Noelie
>
A useful reference on this topic is:
Sverker Johansson
>
> Greetings,
>
> Is there an extant species (sensu "interfertile in the wild") of
> vertebrates where the chromosome count is not consistent
> across all of the (fertile) members of the population, and
> where individuals of differing chromosome counts mate
> (i.e., produce offspring) indiscriminately?
Yes. It's common among mice (ordinary common house mice)
which have lots of chromosomal races, that are generally not
reproductively isolated in the wild.
Some references:
Hauffe, H C & Pialek, J (1997) 'Evolution of the chromosomal races
of Mus musculus domesticus in the Rhaetina alps: the roles of
whole-arm reciprocal translocation and zonal raciation',
Biol J Linn Soc 62:255-278
Britton-Davidian et al (2000) 'Rapid chromosomal evolution in
island mice', Nature 403:158
Said et al (1999) 'Is chromosomal speciation occurring in house
mice in Tunisia?', Biol J Linn Soc 68:387-399
--
Best regards, HLK, Physics
Sverker Johansson U of Jonkoping
----------------------------------------------
Definitions:
Micro-evolution: evolution for which the evidence is so
overwhelming that even the ICR can't deny it.
Macro-evolution: evolution which is only proven beyond
reasonable doubt, not beyond unreasonable doubt.
Sverker Johansson
Exactly what happened in the human-chimp split
(presumably including the Kama Sutra reference,
if I know the participants correctly).
Two chromosomes in the ancestor fused to become
a single chromosome in humans. Details in:
http://www.gate.net/~rwms/hum_ape_chrom.html
The web page above also contains references to
chromosomal variation in cattle and sheep (as
well as another mouse ref).
Since several of the best-studied species of
vertebrates (ourselves, our pets, and our pests)
turn out to have chromosomal races of the kind
you asked for, it is reasonable to conclude
that they are likely to be common among vertebrates
in general.
wilkins
> "Noelie S. Alito" wrote:
> >
> > Greetings,
> >
> > Is there an extant species (sensu "interfertile in the wild") of
> > vertebrates where the chromosome count is not consistent
> > across all of the (fertile) members of the population, and
> > where individuals of differing chromosome counts mate
> > (i.e., produce offspring) indiscriminately?
>
> Yes. It's common among mice (ordinary common house mice)
> which have lots of chromosomal races, that are generally not
> reproductively isolated in the wild.
>
> Some references:
>
> Hauffe, H C & Pialek, J (1997) 'Evolution of the chromosomal races
> of Mus musculus domesticus in the Rhaetina alps: the roles of
> whole-arm reciprocal translocation and zonal raciation',
> Biol J Linn Soc 62:255-278
>
> Britton-Davidian et al (2000) 'Rapid chromosomal evolution in
> island mice', Nature 403:158
>
> Said et al (1999) 'Is chromosomal speciation occurring in house
> mice in Tunisia?', Biol J Linn Soc 68:387-399
And my favourite: the Israeli Naked Mole Rat which has four chromosomal
races, each of which is interfertile with only one of the others, but
which form a ring of racial interbreeding. The leading expert on them,
Eviatar Nevo, calls them a superspecies.
Similar results obtain on prarie dogs, and Canadian lemmings (?) I
recall.
--
John Wilkins, Head, Communication Services, The Walter and Eliza Hall
Institute of Medical Research, Melbourne, Australia
Homo homini aut deus aut lupus - Erasmus of Rotterdam
<http://www.users.bigpond.com/thewilkins/darwiniana.html>
Stephen F. Schaffner
wilkins <wil...@wehi.edu.au> wrote:
>Sverker Johansson <l...@hlk.no.hj.spam.se> wrote:
>> Yes. It's common among mice (ordinary common house mice)
>> which have lots of chromosomal races, that are generally not
>> reproductively isolated in the wild.
>>
>> Some references:
>>
>> Hauffe, H C & Pialek, J (1997) 'Evolution of the chromosomal races
>> of Mus musculus domesticus in the Rhaetina alps: the roles of
>> whole-arm reciprocal translocation and zonal raciation',
>> Biol J Linn Soc 62:255-278
>>
>> Britton-Davidian et al (2000) 'Rapid chromosomal evolution in
>> island mice', Nature 403:158
>>
>> Said et al (1999) 'Is chromosomal speciation occurring in house
>> mice in Tunisia?', Biol J Linn Soc 68:387-399
>
>And my favourite: the Israeli Naked Mole Rat which has four chromosomal
>races, each of which is interfertile with only one of the others, but
>which form a ring of racial interbreeding. The leading expert on them,
>Eviatar Nevo, calls them a superspecies.
How can they form a ring if each is only interfertile with one
other race?
--
Steve Schaffner s...@genome.wi.mit.edu
SLAC and I have a deal: they don't || Immediate assurance is an excellent sign
pay me, and I don't speak for them. || of probable lack of insight into the
|| topic. Josiah Royce
Noelie S. Alito
"Todd A. Farmerie" <farm...@interfold.com> wrote in message
news:3ADD0E4F...@interfold.com...
> "Noelie S. Alito" wrote:
> >
> > Greetings,
> >
> > Is there an extant species (sensu "interfertile in the wild") of
> > vertebrates where the chromosome count is not consistent
> > across all of the (fertile) members of the population, and
> > where individuals of differing chromosome counts mate
> > (i.e., produce offspring) indiscriminately?
>
> the two "species" of horse (domestic and Przewalski). Once
> viewed as subspecies, they are fully capable of interbreeding to
> produce fertile offspring. (They have come to be viewed as two
> separate species based primarily on their having different
> chromosome numbers.)
Actually, I wondered about that. Before I received all of these
responses indicating that it is relatively common, it occurred to
me that classifiers might be inappropriately assigning individuals
to different species based solely on the differing chromosome
counts, even though, functionally and behaviorally, it makes no
difference to the two individuals involved. (It would seem that
that particular definition of "species" is worthless.)
Noelie
--
marine -- adj (Fr) more expensive. "He cashed his bearer bonds
so he could buy ~ hoses and ~ varnish"
howard hershey
Floyd wrote:
>
> Noelie S. Alito <noe...@nospam.jump.net> wrote in article
> <9bi0bm$313$1...@news.jump.net>...
> > Greetings,
> >
> > Is there an extant species (sensu "interfertile in the wild") of
> > vertebrates where the chromosome count is not consistent
> > across all of the (fertile) members of the population, and
> > where individuals of differing chromosome counts mate
> > (i.e., produce offspring) indiscriminately?
> >
> > Enquiring minds want to know!
>
> Some humans with trisomy 21 are fertile (I'm not sure, offhand, if their
> children are also fertile, but I know they inherit the additional
> chromosome). HTH
> -Floyd
Most, however, are not. That is not a consequence of having an extra
chromosome, per se. It is a consequence of the fact that one of the
phenotypic defects of trisomy for some of the genes that reside on
chromosome 21 involves the development of the reproductive system.
OTOH, individuals with XYY syndrome (but not XXY/Kleinfelter's, where,
again, developmental problems interfere) are quite fertile. They do
not usually pass on the extra Y, but I am not sure why. Have to look
that up. My guess is that it gets lost because it does not have a
chiasmata with the X.
Ken Cox
> Ken Cox wrote:
> > "Noelie S. Alito" wrote:
> > > What are Robertsonian translocations and don't they hurt?
> >
> > http://gslc.genetics.utah.edu/disorders/karyotype/translocbkg.html
> Exactly what happened in the human-chimp split
> (presumably including the Kama Sutra reference,
> if I know the participants correctly).
>
> Two chromosomes in the ancestor fused to become
> a single chromosome in humans. Details in:
> http://www.gate.net/~rwms/hum_ape_chrom.html
Are you sure? If I'm reading the two pages correctly,
Robertsonian fusion *loses* the short arms, and the
two centromeres fuse into one. In the human-chimp
split, the two chimp chromosomes fused at their short
ends, with little loss of material -- the old chimp
2q centromere, and even some of the old telomere,
are still detectable.
Perhaps I am reading the Robertsonian translocation
page in too rigid a fashion, and it does allow for
end-to-end joinings?
--
Ken Cox k...@research.bell-labs.com
howard hershey
Such translocations can lead to reduced fertility (actually it is
usually death of zygotes rather than fertility itself that is
involved) because meiosis can (but does not always) produce gametes
with losses or gains of large chunks of genetic information from a
translocation heterozygote. In theory and often in practice, a
quarter of gametes should have a major deletion and a reciprocal
quarter should have the opposite major gain. The other two quarters
of gametes will have a normal set of genetic information, but will
differ in how that information is divided up into its chromosomes.
This heterozygote underfitness can provide pressure for increasing
reproductive isolation between a population with one arrangement of
chromosomes relative to another population with a different arrangement.
The mule is viable because the half-genomes it gets from the horse and
from the ass are genetically similar enough that development, while
different from either parent species, is quite compatible with life.
[Interestingly enough, the direction of cross makes a practical
difference. The mule (jackass/mare) is a strong worker, whereas the
hinney (she-ass/stallion) is not as valuable. Perhaps this is due to a
difference in mitochondrial genes?]
But the mule is sterile because the two half-genomes have more than
one re-arrangement when you compare the half-genome it got from the
ass and the half-genome it got from the horse. Thus, when the mule
undergoes meiosis, a large fraction of its gametes have at least one
major loss or gain of genetic information and the chance of a gamete
with a complete 'normal' set of information in a sperm or egg occurs
only about once in Blue Moon (the name given to the progeny of one
such mule).
That is, the two species are incompletely separated and can, in
principle, have a very tiny amount of interspecies gene transfer.
That is part of the intermediacy of species formation.
In two sunflower species, similarly, the hybrid is viable but
'infertile', but in that case the frequency of 'anomolous fertility'
runs about 5% .
>
> --
> Ken Cox k...@research.bell-labs.com
Sverker Johansson
Or possibly I'm applying it too loosely -- I'm no
geneticist. But it's quite obvious that an end-to-end
joining for all practical purposes has taken place.
Matter of definition whether to call it Robertsonian
or not.
In any case, IIRC Robertsonian translocation is common
enough in the origin of chromosomal races. It is
unlikely that translocation involving significant loss
of material would be viable.
Alternatively, if you look at the picture with the
chromosomes side by side at that website, you'll see that
the different apes have the centromeres in different
position. If the ancestral state matches the orangutang,
the short arms can be lost without actually losing
all that much. This requires the centromeres moving around
a bit in the other lineages, but they have to do that
anyway, since no two apes (us included) have both of them
in the same position.
Todd A. Farmerie
>
> The mule is viable because the half-genomes it gets from the horse and
> from the ass are genetically similar enough that development, while
> different from either parent species, is quite compatible with life.
> [Interestingly enough, the direction of cross makes a practical
> difference. The mule (jackass/mare) is a strong worker, whereas the
> hinney (she-ass/stallion) is not as valuable. Perhaps this is due to a
> difference in mitochondrial genes?]
IIRC, it is due to maternal imprinting (methylation).
taf
Noelie S. Alito
>
>
> Ken Cox wrote:
> >
> > "Noelie S. Alito" wrote:
> > > What are Robertsonian translocations and don't they hurt?
> >
> > http://gslc.genetics.utah.edu/disorders/karyotype/translocbkg.html
> >
> > A form of chromosome fusion, two chromosomes become one,
> > with the loss of the short arms. The resulting mutant
> > may still be fertile, because the two chromosomes from
> > his/her mate can line up with her/his single one.
>
> Such translocations can lead to reduced fertility (actually it is
> usually death of zygotes rather than fertility itself that is
> involved) because meiosis can (but does not always) produce gametes
> with losses or gains of large chunks of genetic information from a
> translocation heterozygote. In theory and often in practice, a
> quarter of gametes should have a major deletion and a reciprocal
> quarter should have the opposite major gain. The other two quarters
> of gametes will have a normal set of genetic information, but will
> differ in how that information is divided up into its chromosomes.
> This heterozygote underfitness can provide pressure for increasing
> reproductive isolation between a population with one arrangement of
> chromosomes relative to another population with a different arrangement.
In a link off of the aforementioned Robertsonian T. page there is
a little quiz about that
http://gslc.genetics.utah.edu/disorders/karyotype/segregation.html
Noelie
--
Everything you've learned in school as "obvious"
becomes less and less obvious as you begin to
study the universe. For example, there are no
solids in the universe. There's not even a
suggestion of a solid. There are no absolute
continuums. There are no surfaces. There are
no straight lines.
-- R. Buckminster Fuller
John Edstrom
: "howard hershey" <hers...@indiana.edu> wrote in message
: news:3ADDBC1B...@indiana.edu...
:>
:>
:> Ken Cox wrote:
:> >
:> > "Noelie S. Alito" wrote:
:> > > What are Robertsonian translocations and don't they hurt?
:> >
:> > http://gslc.genetics.utah.edu/disorders/karyotype/translocbkg.html
:> >
Here is a literature review. This is not my field. Could somebody
who knows more comment on how reasonable it is, or are the examples
given 'flakey?' It gives a lot more examples and is more optomistic
about the fertility of individuals with Robertsonian translocations.
http://www.grisda.org/origins/11067.htm
:> > A form of chromosome fusion, two chromosomes become one,
:> > with the loss of the short arms. The resulting mutant
:> > may still be fertile, because the two chromosomes from
:> > his/her mate can line up with her/his single one.
...
: Noelie
: --
: Everything you've learned in school as "obvious"
: becomes less and less obvious as you begin to
: study the universe. For example, there are no
: solids in the universe. There's not even a
: suggestion of a solid. There are no absolute
: continuums. There are no surfaces. There are
: no straight lines.
: -- R. Buckminster Fuller
--
John Edstrom | edstrom @ teleport.com
John Wilkins
> In article <1es2k7d.4tq49cxy5edwN%wil...@wehi.edu.au>,
> wilkins <wil...@wehi.edu.au> wrote:
> >Sverker Johansson <l...@hlk.no.hj.spam.se> wrote:
>
> >> Yes. It's common among mice (ordinary common house mice)
> >> which have lots of chromosomal races, that are generally not
> >> reproductively isolated in the wild.
> >>
> >> Some references:
> >>
> >> Hauffe, H C & Pialek, J (1997) 'Evolution of the chromosomal races
> >> of Mus musculus domesticus in the Rhaetina alps: the roles of
> >> whole-arm reciprocal translocation and zonal raciation',
> >> Biol J Linn Soc 62:255-278
> >>
> >> Britton-Davidian et al (2000) 'Rapid chromosomal evolution in
> >> island mice', Nature 403:158
> >>
> >> Said et al (1999) 'Is chromosomal speciation occurring in house
> >> mice in Tunisia?', Biol J Linn Soc 68:387-399
> >
> >And my favourite: the Israeli Naked Mole Rat which has four chromosomal
> >races, each of which is interfertile with only one of the others, but
> >which form a ring of racial interbreeding. The leading expert on them,
> >Eviatar Nevo, calls them a superspecies.
>
> How can they form a ring if each is only interfertile with one
> other race?
D'oh! I mean infertile with one of the others.
--
John Wilkins at home
<http://www.users.bigpond.com/thewilkins/darwiniana.html>
mel turner
>Is there an extant species (sensu "interfertile in the wild") of
>vertebrates where the chromosome count is not consistent
>across all of the (fertile) members of the population, and
>where individuals of differing chromosome counts mate
>(i.e., produce offspring) indiscriminately?
As promised yesterday, here are some results of a lit.
search on "chromosom* and robertsonian and polymorphi*"
[looking for reports on chromosomally polymorphic species
and populations].
Many species are polymorphic with regard to their karyotypes
[i.e., their particular chromosome complements]. Some do vary
within single populations. Ones that vary geographically may
still show polymorphic populations in the zones where different
chromosome races meet. Organisms heterozygous for Robertsonian
fissions or fusions can still be very fertile if the heterozygosity
doesn't interfere with meiosis.
TI: Genetic differentiation in populations polymorphic for
Robertsonian translocations.
AU: GREGORIUS-H-R; HERZOG-S
SO: HEREDITY 62(3): 307-314.
PY: 1989
AB: Robertsonian translocations are characterized by centric fusion
of two non-homologous acro- or telocentric chromosomes. Such
translocations can be maintained in populations if in the
chromosomally heterozygous individuals meiosis takes place regularly.
In this case the question arises as to the existence of secondary
isolating mechanisms that inhibit genetic exchange between the
translocation chromosomes and their non-fused counterparts. The
present paper treats this question by analyzing simultaneous changes
at two gene loci, one located on each of the two constituent
chromosomes. The analytic results are discussed in terms of
opportunities for genetic differentiation to occur within a population
polymorphic for Robertsonian translocations and are opposed to current
theories on this subject.
Shrews are evidently big on polymorphisms
TI: The complex hybrid zone between the Abisko and Sidensjo chromosome
races of Sorex araneus in Sweden.
AU: Fredga-Karl {a}; Narain-Yolanda
SO: Biological-Journal-of-the-Linnean-Society. [print] June, 2000; 70
(2): 285-307..
AB: Six chromosome races of the common shrew occur in Sweden, each with
its characteristic arm combination of metacentric chromosomes. G-banded
karyotypes were analysed from 201 common shrews in 14 localities of the
northern hybrid zone in Sweden. [SNIP]
Chromosome polymorphism of Robertsonian type was common and 43 different
karyotypes were found among the specimens studied.[SNIP]
The extension of the Sidensjo race is comparatively narrow (c. 50 km
in the region of the investigation), and it is regarded to be a 'hybrid
race' between the Uppsala race, which colonized Sweden from the
south-west, and the Abisko race which arrived from the north-east after
the most recent glaciation. The origin of the Sidensjo race is thus
less than 10 000 years old, because earlier this area was covered by
glacial ice.
TI: A potential model for early stages of chromosomal evolution via
concentric Robertsonian fans: A large area of polymorphism in southern
short-tailed shrews (Blarina carolinensis).
AU: Qumsiyeh-M-B {a}; Barker-S; Dover-S; Kennedy-P-K; Kennedy-M-P
SO: Cytogenetics-and-Cell-Genetics. 1999; 87 (1-2): 27-31..
AB:Western Tennessee contains unusually highly polymorphic populations
of southern short-tailed shrews (Blarina carolinensis). We previously
documented eight Robertsonian translocations (ROBs) accounting for a
variation in diploid number from 46 in most of this species' range to
34-40 in western Tennessee. We have now expanded our study to include
data from adjacent areas in Tennessee and Mississippi, 10 localities in
all. The new data show a variation in diploid number ranging from 31 to
41, four new ROBs (for a total of 12), and the novel finding of
monobrachial translocations in this group. All animals collected from
this large area (extending over 12,000 km2) had some level of ROBs,and
none represented the 2n = 46 form seen in other parts of the range of
this species. [SNIP]
There was a concentric pattern to the evolution and presumed spreading
of the ROBs. This allowed us to expand the concept of a Robertsonian
"fan," introduced by Matthey (1970), to that of concentric evolution
of multiple fusion fans: ROBs likely arose independently, separated
temporally and geographically, and radiated into surrounding populations
to create this complex zone of polymorphism. This is an active process
in its infancy, and it is not as mature as that seen in European studies
of Mus and Sorex.
TI: Geography of chromosomes in natural populations of Sorex araneus
and Suncus murinus.
AU: Polyakov-A-V; Rogacheva-M-B; Borodin-P-M
SO: Genetika-. Aug., 1997; 33 (8) 1126-1132..
LA: Russian; Non-English
AB: The geographic distribution of chromosome races of two shrew
species (Sorex araneus and Suncus murinus) was analyzed on the basis
of published data and personal results. It was shown that expansion of
both species was accompanied by fixation of different chromosome
rearrangements (mainly Robertsonian translocations) in isolates.
Chromosome polymorphism studied from the viewpoint of ecology and
geography of these species allows reconstruction of their evolutionary
history and understanding of the speciation process.
TI: Meiotic drive favors Robertsonian metacentric chromosomes in the
common shrew (Sorex araneus, Insectivora, Mammalia).
AU: Wyttenbach-A {a}; Borodin-P; Hausser-J
SO: Cytogenetics-and-Cell-Genetics. 1998; 83 (3-4) 199-206..
AB: Meiotic drive has attracted much interest because it concerns the
robustness of Mendelian segregation and its genetic and evolutionary
stability. We studied chromosomal meiotic drive in the common shrew
(Sorex araneus, Insectivora, Mammalia), which exhibits one of the
most remarkable chromosomal polymorphismswithin mammalian species.
[SNIP]
TI: The number of karyotypic variants in the common shrew Sorex
araneus.
AU: ZIMA-J; WOJCIK-J-M; HORAKOVA-M
SO: ACTA THERIOLOGICA 33(26-43): 467-476.
PY: 1988
AB: Owing to intensive research carried out in different countries, a
very complicated variation of common shrew karyotype was revealed,
including polymorphism and polytypy. Thirty-seven different
Robertsonian metacentrics, 13 different homozygous karyotypes
containing only metacentric autosomes, and about 30 different
homozygous karyotypes containing metacentric and acrocentric autosomes
have actually been found in natural populations. [SNIP]
And rodents:
TI: Mitochondrial DNA variation and the evolution of Robertsonian
chromosomal races of house mice, Mus domesticus.
AU: Nachman-Michael-W {a}; Boyer-Sarah-N {a}; Searle-Jeremy-B;
Aquadro-Charles-F {a}
SO: Genetics-. 1994; 136 (3) 1105-1120..
AB:The house mouse, Mus domesticus, includes many distinct Robertsonian
(Rb) chromosomal races with diploid numbers from 2n = 22 to 2n = 38.
Although these races are highly differentiated karyotypically, they are
otherwise indistinguishable from standard karyotype (i.e., 2n = 40)
mice, and consequently their evolutionary histories are not well
understood. We have examined mitochondrial DNA (mtDNA) sequence
variation from the control region and the ND3 gene region among 56 M.
domesticus from Western Europe, including 15 Rb populations and 13
standard karyotype populations, and two individuals of the sister
species, Mus musculus. mtDNA exhibited an average sequence divergence
of 0.84% within M. domesticus and 3.4% between M. domesticus and M.
musculus. The transition/transversion bias for the regions sequenced is
5.7:1, and the overall rate of sequence evolution is approximately 10%
divergence per million years. The amount of mtDNA variation was as
great among different Rb races as among different populations of
standard karyotype mice, suggesting that different Rb races do not
derive from a single recent maternal lineage. Phylogenetic analysis
of the mtDNA sequences resulted in a parsimony tree which contained
six major clades. Each of these clades contained both Rb and standard
karyotype mice, consistent with the hypothesis that Rb races have
arisen independently multiple times. Discordance between phylogeny
and geography was attributable to ancestral polymorphism as a
consequence of the recent colonization of Western Europe by mice.
Two major mtDNA lineages were geographically localized and contained
both Rb and standard karyotype mice. The age of these lineages suggests
that mice have moved into Europe only within the last 10,000 years and
that Rb populations in different geographic regions arose during this
time.
So, house mice chromosome numbers have quite a range [diploid
numbers from 22 up to 40].
TI: Morphometric variability in karyologically polymorphic populations
of the wild Mus musculus domesticus in Greece.
AU: Chondropoulos-Basil-P; Fraguedakis-Tsolis-Stella-E;
Markakis-George; Giagia-Athanasopoulou-Eva
SO: Acta-Theriologica. 1996; 41 (4) 375-382..
TI: Population genetic structure in a Robertsonian race of house mice:
Evidence from microsatellite polymorphism.
AU: Dallas-J-F {a}; Bonhomme-F; Boursot-P; Britton-Davidian-J; Bauchau-V
SO: Heredity-. Jan., 1998; 80 (1) 70-77..
AB: Genetic evidence was assessed for inbreeding and population
subdivision in a Robertsonian fusion (Rb) race of the western European
form of house mouse, Mus musculus domesticus, in central Belgium.
Inbreeding, and the factors responsible for subdivision (genetic drift
and extinction-recolonization) can theoretically influence the fixation
of underdominant Rb variants. [SNIP]
These results suggest that both the lack of inbreeding, and the combined
effects of genetic drift and extinction-recolonization, may promote Rb
polymorphism in M. m. domesticus.
TI: Speciation and adaptive radiation of subterranean mole rats,
Spalax ehrenbergi superspecies, in Jordan.
AU: Nevo-Eviatar {a}; Ivanitskaya-Elena; Filippucci-Maria-Gracia;
Beiles-Avigdor
SO: Biological-Journal-of-the-Linnean-Society. Feb., 2000; 69 (2):
263-281..
AB: The major initial mechanism of speciation in subterranean blind
mole rats, Spalacidae, is chromosomal, primarily through Robertsonian
rearrangements. Here we highlight another scenario of chromosomal
rearrangement leading to ecological speciation and adaptive radiation
apparently initiated by pericentric inversions and genic divergence to
different ecologies in mole rats in Jordan. [SNIP]
By a combination of chromosome morphology, genetic distance, body
size and ecogeography, we identified four new putative biological
species. [SNIP]
TI: Patterns of evolution in Graomys griseoflavus (Rodentia, Muridae).
IV. A case of rapid speciation.
AU: Theiler-G-R; Gardenal-C-N; Blanco-A {a}
SO: Journal-of-Evolutionary-Biology. Sept., 1999; 12 (5): 970-979..
AB: The South American group of rodents known as Graomys griseoflavus
comprises two sibling species differing only in diploid chromosomal
complement: G. griseoflavus (2n = 36, 37 and 38) and G. centralis (2n
= 42). Reproductive barriers comprising postzygotic as well as
precopulatory mechanisms prevent gene exchange between these species.
[SNIP]
Lack of correlation between gene flow levels and geographical distance
between population pairs would indicate a recent and fast colonization
of its distribution areas by the derived species. It is possible that
fixation of Robertsonian fusions occurred in a marginal deme of the
ancestral species, e.g. in a parapatric geographical context.
TI: Patterns of evolution in Graomys griseoflavus (Rodentia: Muridae):
II. Reproductive isolation between cytotypes.
AU: Theiler-Gerardo-R; Blanco-Antonio
SO: Journal-of-Mammalogy. 1996; 77 (3) 776-784..
AB: Graomys griseoflavus is a South American murid rodent exhibiting
marked chromosomal polymorphism. Breeding experiments between
individuals from six populations, four showing diploid complements of
36, 37, or 38 and two having 2n = 42, were conducted. Interpopulation
crosses showed that 2n = 36-38 animals were interfertile, indicating
that these cytotypes belong to a single species complex. This species
complex is isolated reproductively from the 2n = 42 chromosomal race.
Chromosomal speciation may have been attained through multiple
sequential Robertsonian fusions. Isolation is asymmetric; matings
between 2n = 42 males and 2n = 36-38 females produced hybrid offspring,
whereas reciprocal crosses were non viable. These results are
compatible with Kaneshiro's hypothesis. Hybrid males were sterile,
backcrosses were productive in ca. 23% of matings between female
hybrids and males of the parental populations, and reciprocal
backcrosses were unsuccessful. Results indicate that the 2n = 42
cytotype is a separate sibling species from those of the 2n = 36-38
complex.
TI: Cytogenetic analysis of autosomal polymorphism in Graomys
griseoflavus (Rodentia, Cricetidae).
AU: Zambelli-A {a}; Vidal-Rioja-Lidia {a}; Wainberg-R
SO: Zeitschrift-fuer-Saeugetierkunde. 1994; 59 (1) 14-20..
AB: South American phyllotine Graomys griseoflavus specimens were
collected in eight localities of central Argentina and
cytogenetically analysed. These populations comprised the following
karyomorphs: 2n = 42, 41, 38, 37, 36, 35 and 34. These chromosome
polymorphisms resulted from Robertsonian fusions (RFs). A
pericentric inversion (PI) in two different autosomal pairs are
described. The numerical karyotype variability is explained by
successive RFs, starting from a karyotype with 2n = 42.
TI:Chromosome polymorphism in Ctenomys minutus (Rodentia-Octodontidae).
AU: De-Freitas-Thales-Renato-O
SO: Brazilian-Journal-of-Genetics. 1997; 20 (1) 1-7..
AB: A sample of 101 specimens of Ctenomys minutus was collected along
its geographic range. Eight karyotypes (2n = 42, 45, 46a, 46b, 47, 48,
49 and 50) were found. The chromosome polymorphisms were due to
Robertsonian rearrangements and tandem fusions. The distribution of
polymorphisms indicated three population blocks: northern (2n = 49 and
50), central (2n = 46a, 47, and 48) and southern (2n = 42, 45, and
46b). These findings suggest that this species is undergoing a
speciation process due to geographic isolation.
TI: New Ctenomys karyotype (Rodentia, Octodontidae) from northeastern
Argentina and from Paraguay confirm the extreme chromosomal
multiformity of the genus.
AU: ORTELLS-M-O; CONTRERAS-J-R; REIG-O-A
SO: GENETICA (DORDRECHT) 82(3): 189-202.
PY: 1990
AB: Bone-marrow karyotypes of 68 specimens of the subterranean
octodontid rodent genus Ctenomys from 16 different populations of
northeast Argentina and one from Paraguay have been studied. A
surprising variety of chromosome numbers was found, ranging from 2n =
42 to 2n = 70. Some of the karyomorphs are clearly assigned to named
species by topotypy: C. conoveris 2n = 50, FN = 56; C. argentinus, 2n =
44, FN = 54; C. perrensi, 2n = 50 FN = 84; C. dorbignyi, 2n = 70, FN =
84; C. roigi, 2n = 48, FN = 80; C. yolandae, 2n = 50, FN = 78. Four
populations of Corrientes Province similar in morphology to C. perrensi
were found to be polymorphic and polytypic; they maintain the same FN =
84, but diploid numbers increase from 2n = 54 to 2n = 58 from SW to the
NE, thus suggesting Robertsonian rearrangements. In the middle of this
cline, a stable karyomorph of 2n = 62, FN = 84 was found in two
different populations, suggesting to belong to an undescribed species.
Another karyomorph of 2n = 42, FN = 76 found in Curuzu Laurel,
Corrientes, may also prove to represent another undescribed species.
One karyomorph of 2n = 52, FN = 74, and another of 2n = 56, FN = 78
from Parana and Ubajay (Entre Rios Province, Argentina) respectively
are close to C. rionegrensis. The relationships among these karyomorphs
is considered in light of data on sperm morphology. The hypothesis is
advanced that karyotypic rearrangements among the FN = 84 group may be
the result of Robertsonian repatterning from a 2n = 70 original
widespread form. Fixation of chromosomal variants is correlated with
patchy distribution and small size of unstable demes, and may or may
not have resulted in reproductive isolation.
TI: Multiple autosomal polymorphism in populations of Akodon simulator
simulator Thomas, 1916 from Tucuman, Argentina (Rodentia, Cricetidae).
AU: LIASCOVICH-R-C; BARQUEZ-R-M; REIG-O-A
SO: GENETICA (DORDRECHT) 82(3): 165-176.
PY: 1990
AB: Cytogenetic analysis was performed on twenty seven specimens of
Akodon simulator simulator collected in three different localities of
Tucuman Province, Argentina. Diploid number, chromosomal morphology
and C and G banding patterns were studied. Eight different karyomorphs
were found, with diploid numbers of 2n = 38, 39, 40, 41, and 42. All
individuals showed the same number of chromosomal arms (FN = 42).
G-bands enable to identify chromosomal pairs (1, 10, 11, 12, 13, and 14)
involved in three centric fusions. C-bands revealed that the
heterochromatin is located in centromeric regions of the telocentric and
biarmed chromosomes. The present study allowed us to document a new
example of a floating multiple Robertsonian fusion polymorphism. The
data are discussed in relation to the occurrence of Robertsonian
polymorphism in natural populations.
TI: Chromosomal variation in the scrub mouse Akodon molinae (Rodentia:
Sigmodontinae) in central Argentina.
AU: Tiranti-Sergio-I {a}
SO: Texas-Journal-of-Science. Aug., 1998; 50 (3) 223-228..
AB: A cytogenetic study of 34 specimens of the scrub mouse Akodon
molinae from nine localities in La Pampa and San Luis provinces of
central Argentina revealed 2n=43 in 18 specimens, 2n = 44 in eight and
2n = 42 in eight individuals. This variation results from a Robertsonian
polymorphism involving chromosome pair 1. Information on the
distribution and biogeography of Akodon molinae is provided for central
Argentina.
Large mammals do it too, such as anoas [wild buffalos]:
TI: Molecular and chromosomal evolution in anoas (Bovidae: Bubalus sp.).
AU: Schreiber-Arnd {a}; Noetzold-G; Held-Manuela
SO: Zeitschrift-fuer-Zoologische-Systematik-und-Evolutionsforschung.
1993; 31 (1) 64-79..
AB: As a contribution to their taxonomy, population genetic data on
zoo-living anoas are reported, and a review of the history of the
captive stock is provided. Four different chromosome numbers of 44, 45,
47 and 48 chromosomes have been found, respectively, when karyotyping
captive anoas descending from three breeding lines. The number of
chromosome arms is 60 throughout, indicating that Robertsonian
rearrangements are responsible for this cytogenetic variation. [snip]
TI: Cytogenetic analysis (GTG, CBG and NOR bands) of a wild boar
population (Sus scrofa scrofa) with chromosomal polymorphism in the
south-east of Spain.
AU: ARROYO-NOMBELA-J-J; RODRIGUEZ-MURCIA-C; ABAIGAR-T; VERICAD-J-R
SO: GENETICS SELECTION EVOLUTION 22(1): 1-10.
PY: 1990
AB: The karyotypes of 12 wild boars (4 male , 8 female ) from
populations in Sierra Nevada and Sierra de Baza (Almeria) were
analysed. Chromosomal polymorphism giving rise to 3 variants in the
diploid number (2n = 38 (1 male ), 2n = 37 (2 male , 1 female ) and
2n = 36 (1 male , 7 female )) was observed. By means of GTC-band
analysis, this polymorphism proved to be the consequence of a
Robertsonian translocation between members of pairs 15 and 17 of
karyotypes with 2n = 38, thereby creating a long submetacentric
chromosome (15/17) together with 2 free acrocentric chromosomes [SNIP]
And lizards:
TI: A new derived and highly polymorphic chromosmal race of Liolaemus
monticola (Iguanidae) from the 'Norte Chico' of Chile.
AU: Lamborot-Madeleine {a}
SO: Chromosome-Research. June, 1998; 6 (4) 247-254..
AB: A multiple Robertsonian fission chromosomal race of the Liolaemus
monticola complex in Chile is described and is shown to be the most
derived and the most complex among the Liolaemus examined thus far.
The 29 karyotyped lizards analysed from the locality of Mina Hierro
Viejo, Petorca, Provincia de Valparaiso, Chile, exhibited a diploid
chromosomal number ranging from 42 to 44, and several polymorphisms.
[SNIP]
Karyotypic differences between the Northern (2n = 38-40) and the
Multiple-Fission (2n = 42-44) races were attributed mainly to
Robertsonian fissions, an enlarged chromosome and pericentric
inversions involving the macrochromosomes and one microchromosome
pair.
TI: Extreme chromosomal polytypy in a population of Sceloporus
grammicus (Sauria: Phrynosomatidae) at Santuario Mapethe, Hidalgo,
Mexico.
AU: Goyenechea-Irene {a}; Mendoza-Quijano-Fernando {a};
Flores-Villela-Oscar {a}; Reed-Kent-M
SO: Journal-of-Herpetology. 1996; 30 (1) 39-46..
AB: The karyotypic status of the mesquite lizard, Sceloporus grammicus,
was investigated at two localities at Santuario Mapethe, Hidalgo,
Mexico. A total of 23 different karyotypes was recorded from the 36
individuals examined. Individual lizards were heterozygous at up to
four chromosomes. Karyotypic differences were attributed to
Robertsonian fission/fusions and pericentric inversions involving the
macrochromosomes. The polymorphisms generally conformed to
Hardy-Weinberg equilibrium suggesting a lack of underdominance for most
rearrangements. The extreme chromosomal polytypy observed at Santuario
Mapethe is hypothesized to result from parapatric hybridization
between two chromosome races.
and fish:
TI: Geographic distribution of chromosome and microsatellite DNA
polymorphisms in Oncorhynchus mykiss native to western Washington.
AU: Ostberg-Carl-O; Thorgaard-Gary-H {a}
SO: Copeia-. May, 1999; 199 (2): 287-298..
AB: Chromosome studies of native populations of Oncorhynchus mykiss
(steelhead and rainbow trout) in western Washington and southern
British Columbia revealed the presence of two evolutionarily distinct
chromosome lineages. Populations between, and including, the Elwha
River, Washington, and Chilliwack River, British Columbia, contained
2n = 60 chromosomes. Populations on the central Washington coast
contained 2n = 58 chromosomes. The north Washington coast and western
Strait of Juan de Fuca contained individuals with 58, 59, or 60
chromosomes, suggesting this is a transition zone between 58 and 60
chromosome groups. The differences in chromosomal structure between
2n = 58 and 2n = 60 groups are presumably a Robertsonian rearrangement
and an inversion. [SNIP]
TI: A complex chromosomal polymorphism in Gobius fallax (Gobiidae,
Perciformes).
AU: THODE-G; MARTINEZ-G; RUIZ-J-L; LOPEZ-J-R
SO: GENETICA (DORDRECHT) 76(1): 65-72.
PY: 1988
AB: Chromosome analysis of 53 specimens from a population of Gobius
fallax has revealed inter- and intra-individual variation in the
diploid number (2n = 38-43) arising mainly through Robertsonian
translocations. [SNIP]
TI: Intra-populational and intra-individual mosaicisms of Uranoscopus
scaber L. (Perciformes, Uranoscopidae).
AU: VITTURI-R; CATALANO-E; LO-CONTE-M-R; ALESSI-A-M; AMICO-F-P;
COLOMBERA-D
SO: HEREDITY 67(3): 325-330.
PY: 1991
AB: Karyotypic analysis on 25 specimens of Uranoscopus scaber from the
Gulf of Palermo (Italy) has revealed the occurrence of an intra-
populational mosaicism of Robertsonian type with three distinct diploid
numbers: 2n = 30, 2n = 29 and 2n = 28. Intra-individual mosaicism in
the chromosome number (2n = 30 and 31 in two specimens and 2n = 28 and
29 in one specimen) is also reported.[SNIP]
And arthropods:
TI: Cytogenetics of Australian scorpions: II. Chromosome polymorphism
in species of Urodacus (family Scorpionidae).
AU: SHANAHAN-C-M
SO: GENOME 32(5): 890-900.
PY: 1989
AB: The cytogenetic features of six species of scorpion from the
Australian genus Urodacus (family Scorpionidae) were examined.
Australian scorpionids possess monocentric chromosomes and male
meiosis is achiasmate. Chromosome numbers are generally high and
in some species extremely variable. Chromosome variation in one
spcies, U. manicatus was found to be due to fusion-fission
polymorphism and variation in the number of small telocentric
chromosome pairs. Additionally two populations exhibited extensive
inversion heterozygosity. Available evidence suggests that female
meiosis may also be achiasmate. The extensive numerical and structural
heterozygosity found in U. manicatus may be related to the achiasmate
meiosis, which allows regular pairing and disjunction of the multiple
chromosome associations.
TI: Robertsonian translocations and B chromosomes in the Wellington
tree weta, Hemideina crassidens (Orthoptera: Anostostomatidae).
AU: Morgan-Richards-Mary
SO: Hereditas-Lund. [print] February, 2000; 132 (1): 49-54..
AB: Two karyotypes within the species Hemideina crassidens are
described, 2n = 15 (XO) and 2n = 19 (XO). These two karyotypes have
a NF of 28. The 19-karyotype was found exclusively in the southern
part of the species range and the 15-karyotype was found in the north.
The differences between the two karyotypes are interpreted as arising
from two Robertsonian translocations (fission/fusion). Laboratory
matings between weta with the two karyotypes produced viable offspring.
During meiosis in F1 intraspecific hybrids metacentric and acrocentric
autosomes aligned to form two trivalents, confirming homologies
predicted by Robertsonian translocations. The subspecies H. c.
crassicruris, (confined to Stephens Island) was found to be polymorphic
for a metacentric B chromosome. An unusual association of sex and
presence of B chromosome was observed in this island population with
Bs found only in male weta.
TI: The complex Robertsonian system of Dichroplus pratensis
(Melanoplinae, Acrididae): II. Effects of the fusion polymorphisms
on chiasma frequency and distribution.
AU: BIDAU-C-J
SO: HEREDITY 64(2): 145-159.
PY: 1990
AB: The effects of a complex series of Robertsonian polymorphisms on
chiasma frequency and distribution were analysed in natural population
of the grasshopper Dichroplus pratensis which has a standard karyotype
of 2n = 19 (XO male ) telocentrics. Populations are usually polymorphic
for one to three of seven distinct fusions between the six large
(L-1-L-6) autosomes. [SNIP]
TI: Hybridization of chromosome-polymorphic populations of the
inquiline ant, Doronomyrmex kutteri (Hymenoptera, Formicidae).
AU: BUSCHINGER-A; FISCHER-K
SO: INSECTES SOCIAUX 38(2): 95-104.
PY: 1991
AB: The workerless, inquiline ant, Doronomyrmex kutteri has isolated
populations with a haploid chromosome number of n = 23 both in the
Alps (Swiss and South Tyrolean Alps) and in Sweden, and a population
with n = 25 in southern Germany. Crossbreeding of sexuals from all
populations proved successful. Backcrosses of F1-females with males
from the parental populations produced F2-females, and hybrid males
with n = 23, 24, or 25 chromosomes. The chromosome polymorphism is
not due to B-chromosomes. Probably the n = 25 karyotype originated
from the n = 23 karyotype by two Robertsonian fissions [SNIP]
cheers
howard hershey
----------
In article <3ADDCF5B...@interfold.com>, "Todd A. Farmerie"
<farm...@interfold.com> wrote:
Do you have a source? It seems to me that either could be an explanation
for 'muscle weakness' in one direction rather than the other. There
certainly are maternally inherited muscle traits due to mitochondrial
differences in humans. I really don't know the answer, but would be
interested in reading any source you know of.
>
> taf
>
Todd A. Farmerie
Not that I could lay my hands on - it has been almost a decade
(and a cross country move) since I looked at this issue, which
seemed at the time to be potentilly peripherally related to my
research, but proved irrelevant. I will dig around and see what
I can find.
taf