Cichlid Incest
Julie L.
Can someone please tell me whether fish are fussy about mating with
brothers and sisters? Because when you buy them from shops you can never
be sure whether they are from the same brood, and whether you should just
buy a pair then and there, or take the trouble to hunt around to fins a
mate from a different shop. Do fish from the same brood mate? (this is
obviously genetically dodgy, but they do it anyway?)
Julie
CRFoster
In article <321305...@ast.cam.ac.uk>, "Julie L."
<spec...@ast.cam.ac.uk> writes:
Julie,
Actually, most groups of cichlids found in the same store (if they are
from the same batch) tend to be siblings. They do not seem to mind at all
as to who they breed with (mothers-sons, fathers-daughters,
brothers-sisters). This in itself is not much of a problem. The problem is
that repetitive inbreeding can be genetically damaging to the offspring.
The first few generations will be OK but after multi-generation repetitive
inbreeding the fish begin to develop deformities. In southern California
this is most noticable with Neolamprologus elongatus "brichardi" and N.
elongatus "daffodil." The stock at most of the stores will have
individuals with cranial deformities-their heads are shaped more like
Tropheus sp. than that of the elongatus complex. To battle this, some of
us try to obtain stock from several locations, as well as wild caught
stock to increase genetic diversity. The inbreeding that occurs is one of
the reason that wild caught or F1 fish are more valuable than F3, F4,
Fx... They retain all of the characteristics of the naturally occuring
specimens.
Chuck <CRFo...@aol.com>
Cynthia Teague
(heavily snipped)
some of
>us try to obtain stock from several locations, as well as wild caught
>stock to increase genetic diversity.
I've done this a few times but usually end up raising youngsters from several
breeders in one tank, so that by the time they pair off I have no idea whether
they are siblings or not. Do you actually keep fry from different lines
separate & pair them up appropriately? And how would you do that -- put
males from one line & females from another line together, then let them
pair off on their own? And what about fish that are hard to sex?
Tell me more!
Cynthia Teague
2067...@msu.edu
LEE WENG FOOK
I have kept a population of convicts for about nearly 8 years and they
have been inbreeding (incest included) for generations. initially there
were side effects like weak young and poor survival rates. Then the
situaition improved and the brood survival went up, but the males
attained a much smaller size then expected. They didn't have the
magnificent finnage of a typical male. They look like females except for
a more pointed fin. But they were still able to mate but they were really
shy and were bullied by the females. Then the females got samller. They
were only about the size of a tiger barb when they starttd to breed
producing only about 20 eggs instead of the hundreds. They stayed this
small for all their life. Only in the last 2 years did the population
stablize and the males regaining their size finnage and courage and the
femamales back to the normal size.
----------------------------------
* Jeremy Lee
* School of Biological Sciences
* National University of Singapore
* SCI30749@.NUS.SG
* Exca...@pobox.org.sg
----------------------------------
Cynthia Teague
In article <4vtn3j$6...@nuscc.nus.sg>, sci3...@leonis.nus.sg says...
>
>I have kept a population of convicts for about nearly 8 years and they
>have been inbreeding (incest included) for generations. initially there
>were side effects like weak young and poor survival rates. Then the
>situaition improved and the brood survival went up, but the males
>attained a much smaller size then expected. They didn't have the
>magnificent finnage of a typical male. They look like females except for
>a more pointed fin. But they were still able to mate but they were really
>shy and were bullied by the females. Then the females got samller. They
>were only about the size of a tiger barb when they starttd to breed
>producing only about 20 eggs instead of the hundreds. They stayed this
>small for all their life. Only in the last 2 years did the population
>stablize and the males regaining their size finnage and courage and the
>femamales back to the normal size.
>
convicts in general would breed very young if the opportunity (food, presence
of member of opposite sex, absence of predation) presented itself. And
fish that start breeding young never seem to get as large as their siblings
that wait, at least in my experience.
And of course inbreeding CAN lead to a stable line once deleterious recessives
have been forced out of the gene pool. Most lines fail, though, and the ones
that are left have very little resilience -- their low level of heterozygosity
leaves them little maneuvering room if conditions change. Look at the corn
viruses of the '70s.
Cynthia Teague
2067...@msu.edu