Question

Tatuo Aida investigated the genetic basis of color variation in the Medaka (Aplocheilus latipes), a small fish found naturally in Japan (T. Aida. 1021. Genetics 6:554-573). Aida found that genes at two loci (B, b and R, r) determine the color of the fish: fish with a dominant allele at both loci are brown, fish with a dominant allele only at the B locus are blue, fish with a dominant allele only at the R locus are red and fish with recessive alleles at both loci are white. Aida crossed a homozygous brown fish with a homozygous white fish. He then backcrossed the F1 with the homozygous white parent and obtained 228 brown fish, 230 blue fish, 237 red fish and 222 white fish.

b. Use a chi-square test to compare the observed numbers of backcross progeny with the number expected for independently assorting genes.

            What is the chi square value?

            What is/are the degrees of freedom and the approximate p-value?

            What conclusion can you make from your chi-square results?

c. What results (phenotypic and genotypic ratios) would you expect for a cross between a homozygous red fish and a white fish?

Answer 1

If you Satisfy with Answer, Please give me "Thumb Up". It was very important to me.