Mitotic gene conversion can be as important as meiotic conversion in driving genetic variability in plants and other species without early germline segregation

by Xianqing Jia, Qijun Zhang, Mengmeng Jiang, Ju Huang, Luyao Yu, Milton Brian Traw, Dacheng Tian, Laurence D. Hurst, Sihai Yang

In contrast to common meiotic gene conversion, mitotic gene conversion, because it is so rare, is often ignored as a process influencing allelic diversity. We show that if there is a large enough number of premeiotic cell divisions, as seen in many organisms without early germline sequestration, s uch as plants, this is an unsafe position. From examination of 1.1 million rice plants, we determined that the rate of mitotic gene conversion events, per mitosis, is 2 orders of magnitude lower than the meiotic rate. However, owing to the large number of mitoses between zygote and gamete and becaus e of long mitotic tract lengths, meiotic and mitotic gene conversion can be of approximately equivalent importance in terms of numbers of markers converted from zygote to gamete. This holds even if we assume a low number of premeiotic cell divisions (approximately 40) as witnessed inArabidopsis. A low mitotic rate associated with long tracts is also seen in yeast, suggesting generality of results. For species with many mitoses between each meiotic event, mitotic gene conversion should not be overlooked.

Source: PLoS Biology: Archived Table of Contents - March 22, 2021 Category: Biology Authors: Xianqing Jia Source Type: research