Question

Sample Random Mating Lab

P generation is 2 male and 2 females of sepia eyed, white eyed, irregular facets, vestigial, dumpy, and black body.

1a) The most common phenotype in the F1 generation is usually wild type. Explain why this occurs based on allele frequencies even though the P generation had no wild type.

1b) Explain why different methods can be used to calculate only irregular facets, the allele counting method, compared to other phenotypes

Answer 1

• Even though in P generation the wild type was not taken, its presence in 1st generation can be due to the presence of wild character allele in recessive in nature in the parent generation and got only dominant in the 1st generation.

For example, take wild allele as w and mutant allele as M

so MM * ww - we get Mw generation

If Mw is taken as P generation in which no wild character is expressed and is crossed with another Mw in which no wild character is expressed

Mw * Mw

MM , Mw , ,Mw , ww 1st generation

Wild character is expressed in 1st generation but not in P generation

• Irregular facets is a dominant mutation which causes small eyes with fused ommatidia. This is due to the domination of If mutation.Gene Kruppel (Kr) is known for segmentation of function and is not expreesed in If mutant eye discs. Kr gain of function mutation If provide a way to identify genes that are active during the development of the eye. So any method of allele counting method can be used.

1. Co-dominant inheritance
2. Square root method for Dominant inheritance
3. Hardy-Weinberg equillibrium and statistical test