Question

Formula of type of gametes in crossautosomal trait

Answer 1

To understand how Sturtevant arrived at this conclusion, take a look at the data shown in Figure 6 (Sturtevant, 1913). As you can see, Sturtevant examined recombination events between B (body color), CO (two eye color genes that were closely linked), and R (rudimentary wings), and compared the frequencies of crossover events. When B and CO did not separate, Sturtevant noticed that the "gametic ratio," or presence, of CO/R recombinants was approximately 1:2 (3,454:6,972). However, when a crossover between B/CO (N = 60) occurred, there was a much lower likelihood (approximately 1:6.5) of a crossover between CO/R (N = 9). This finding is indicative of interference.