Vanessa has obtained two true-breeding strains of mice, each homozygous for an i

Question

Vanessa has obtained two true-breeding strains of mice, each homozygous for an independently discovered recessive mutation that prevents the formation of hair on the body. The discoverer of one of the mutant strains calls his mutation naked, and the other researcher calls her strain hairless. To determine whether the two mutations are simply alleles for the same gene, Vanessa crosses naked and hairless mice with each other. All the offspring are phenotypically wild-type. After intercrossing these F1 mice, however, Vanessa observes 115 wild-type mice and 85 mutant mice in the F2.

What is the most likely explanation for the segregation of wild-type and mutant mice in the F2? Are the naked and hairless mutations alleles for the same gene?

Using symbols of your own choosing, indicate the genotypes of the parents, the F1, and each of the phenotypic classes of the F2 progeny. Describe any gene interactions in this set of crosses.

Explanation / Answer

n: nake allele; N: normal allele h: hairless allele; H: normal allele P: 'nake' (nnHH) >< 'hairless' (NNhh) F1: all NnHh (wild type/normal type) Generally, a phenotype is 'said' based on the mutant, so P1 is just said as 'nake' (not as 'nake-normal'), and P2 is as 'hairless' (not as 'normal-hairless') and n this form it is very difficult to understand the exact pattern for this type of inheritance, to choose the best suite for this 115:85 F2 you can use chie-square test statistics to compare the 115:85 with all dominance and epistatic ratios avilable in genetics, so the ratio with which 115:85 is giving the most matching will be the gene action working for this mutation, if it match with ratios of dominance then u can assume that the alleles are of the same gene and if it matches with the ratios of epistatic then the alleles are from the different genes interacting with the genes for hair formation in mice.

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