|
|
|
|
|
|
|
||
Department of Genetics and Center for Human Genetics, Case Western Reserve University School of Medicine and University
Hospitals of Cleveland, Cleveland, Ohio 44106-4955
A checkpoint mechanism operates at the
metaphase/anaphase transition to ensure that a bipolar
spindle is formed and that all the chromosomes are
aligned at the spindle equator before anaphase is initiated. Since mistakes in the segregation of chromosomes during meiosis have particularly disastrous consequences, it seems likely that the meiotic cell division
would be characterized by a stringent metaphase/
anaphase checkpoint. To determine if the presence of
an unaligned chromosome activates the checkpoint and delays anaphase onset during mammalian female meiosis, we investigated meiotic cell cycle progression in
murine oocytes from XO females and control siblings.
Despite the fact that the X chromosome failed to align
at metaphase in a significant proportion of cells, we were unable to detect a delay in anaphase onset. Based
on studies of cell cycle kinetics, the behavior and segregation of the X chromosome, and the aberrant behavior
and segregation of autosomal chromosomes in oocytes
from XO females, we conclude that mammalian female
meiosis lacks chromosome-mediated checkpoint control. The lack of this control mechanism provides a biological explanation for the high incidence of meiotic
nondisjunction in the human female. Furthermore,
since available evidence suggests that a stringent checkpoint mechanism operates during male meiosis, the lack of a comparable checkpoint in females provides a
reason for the difference in the error rate between oogenesis and spermatogenesis.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
