Meiotic recombination ensures the accurate segregation of homologous chromosomes and reshuffles genetic information to generate new combinations of alleles. The rate of meiotic recombination differs between species and is even different between male and female meiosis of the same species. Sex differences have important consequences for population differentiation, sex chromosome evolution, adaptation, and speciation. While a great deal is known about sex differences in overall recombination rates, relatively little is known about how and why sexes differ in recombination. My project is part of a large project in our laboratory aiming to determine whether and how meiotic recombination differ between female and male meiosis in maize. To compare the rates of meiotic recombination between the males and females, we developed genetic markers and examined the recombination rates that occurred in both chromosomal arms and pericentromeric regions using two backcrossed populations B73 x (B73 x Ms71) and (B73 x Ms71) x B73. Of the four examined regions in the hybrid Ms71/B73, three exhibited a higher frequency of male recombination. To confirm our results and to gain additional resolution, we designed additional marker pairs that made it possible to survey the entire maize chromosome 10 from short arm to long arm of Ms71/B73. Our data shows that recombination frequencies are higher in males over the length of this chromosome, with the largest difference being in the end of the long arm. Our results reveal that males in the hybrid Ms71/B73 underwent recombination at a higher frequency than the females in the same line, which opens the door to further research and explanations as to why these differences exist.
Author: Alaina Singh, Biology Major
Advisor: Meixia Zhao, Biology Department
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