Question

1. The allele b gives Drosophila flies a black body, and b+ gives brown, the wild-type phenotype. The allele wx of a separate gene gives waxy wings, and wx+ gives nonwaxy, the wild-type phenotype. The allele cn of a third gene gives cinnabar eyes, and cn+ gives red, the wild-type phenotype. A female heterozygous for these three genes is testcrossed, and 2,424 progeny (you could also use n=2,423) are classified as follows:

   cn+ · wx+ · b	101
   cn · wx+ · b+	768
   cn · wx+ · b	20
   cn+ · wx+ · b+	323
   cn+ · wx · b	848
   cn · wx · b+	101
   cn · wx · b	242
   cn+ · wx · b+	20

   
   

   Calculate the recombinant frequencies for  b-wx,  b-cn, and  wx-cn.

   Which gene is in the middle: b, wx, or cn?

   Screen shot of table in case of formatting issues:

   NOTE: the genotypes in the table below were released on Friday July 10, but there are errors which have been corrected above.

   cn+ · wx · b	101
   cn · wx+ · b+	768
   cn · wx · +b	20
   cn+ · wx+ · b+	323
   cn+ · wx · b	848
   cn · wx · b	101
   cn · wx+ · b	242
   cn+ · wx · b	20

Answer 1

Answer-

A) gene b is in the middle.

B) recombinant frequency between b-wx = 9.99% ; cn-b = 24.97% ; cn-wx = 33.3%

The calculation is given below: