Crossing Over in Chicken Oogenesis: Cytological and Chiasma-Based Genetic Maps of the Chicken Lampbrush Chromosome 1

Publisher Website
Google Scholar
Abstract
Chiasmata in diplotene bivalents are located at the points of physical exchange (crossing-over) between homologous chromosomes. We have studied chiasma distribution within chicken lampbrush chromosome 1 to estimate the crossing-over frequency between chromosome landmarks. The position of the centromere and chromosome region 1q3.3–1q3.6 on lampbrush chromosome 1 were determined by comparative physical mapping of the TTAGGG repeats in the chicken mitotic and lampbrush chromosomes. The comparison of the chiasma (=crossing over)-based genetic distances on chicken chromosome 1 with the genetic linkage map obtained in genetic experiments showed that current genetic distances estimated by the high-resolution genetic mapping of the East Lansing, Compton, and Wageningen chicken reference populations are 1.2–1.9 times longer than those based on chiasma counts. Conceivable reasons for this discrepancy are discussed.

This publication has 0 references indexed in Scilit: