Question on Genomic Imprinting
Dan
Hi. After reviewing the lecture slides and reading the section in the
book (section 11.5) on genomic imprinting, I am still a little unclear
one one aspect of this phenomenon. That is "Why imprinting must be
reset for the next generation".
Why is this important?
Annie
Sorry I wasn't able to check e-mail yesterday.
Each animal gets a complement of chromosomes from its mom and one from
its dad. The mom's is imprinted in one way, and the dad's is
imprinted in another way.
Go back a generation and think about the organism's mom and dad. The
mom received her two sets of chromosomes from a grandmother and a
grandfather, and the dad received his two sets of chromosomes from a
grandmother and a grandfather. The mother first had to erase the
imprints from her own mother and father, and then re-make them all as
maternal imprints. Likewise, the father first had to erase the
imprints from his own mother and father, and then re-make them all as
paternal imprints. If they didn't reset the imprints into "maternal"
and "paternal" versions, then the eggs and sperm would get a random
mix of maternal and paternal imprints, instead of maternal and
paternal imprints, respectively.
-Annie