A direct measurement of crossing over in human prophase oocytes.
The nature of the relationship between crossing over and failed segregation in human oocytes is of obvious interest. A recent paper by Cheng and colleagues provides important insights into the distribution of crossover events (as marked by MLH1 foci) in human oocytes and raises complex questions regarding discrepancies between direct cytological assessment of exchange and measurement of crossing over by linkage analysis.
Hawley
R Scott
RS
Stowers Institute for Medical Research, Kansas City, MO 64110, USA. rsh@stowers.org