Page 4 NAME: Section 2: Problem Soh ing and Data Analysis. This section is worth
ID: 207746 • Letter: P
Question
Page 4 NAME: Section 2: Problem Soh ing and Data Analysis. This section is worth 22 points. 15. You are a senior working on your comprehensive research project in Dr. Venesky's lab on inheritance patterns of autosomally imherited traits in amphibians. In your first experiment, you perfonm a test cruss using a fomak hellbender (a type of salamander) that has a long tail and slimy skin (TSS) th a male that has a short tail and non-slimy skin (ttss). The resulting offspring from this cross are as follows: Long tail and slimy skin: 405 Short tail and non-slimy skin:395 Long tail and non-slimy skin: 102 Short tail and slimy skin:98 Because you are interested in comparing inheritance patterns among species, you conduct another test but now with newts (another species of salamander). The same allk and hellbenders. You cross a female newt that has a TiSs penotype with a male newt with a genotype of nss. The resulting offspring froms this cross are as follows: les control tail length and skin sin in newts Long tail and slimy skin: 245 Short tail and non-slimy skin: 255 Long tail and non-slimy skin: 245 Short tail and slimy skin: 255 Based on these resalts, answer the following questions a) In hellbenders, are the loci for these traits found oo the same chromosome or on different chromosomes? Briefly explain your answ.er. (2poin b) ln newts, are the loci for these traits found on the same chromosome or on different cheomosomes? Briefty explain your answer. 2 poids e) Eor the species whers the losi are Jesated.on the same shromosoms, cakulale the recombination frequency for these loci.4 poiwExplanation / Answer
a) In case of hellbender
If the genes was assorted independently then half the progeny will be non-recombinant & half the progeny will be recombinant. But in this case ratio of non-recombinant & recombinant is 8:2 (as 800 & 200 in number they are). So they are not assorting independently. So they must be linked with some crossing over. So, they must be present in the same chromosome.
b) In case of newts
If the genes was assorted independently then half the progeny will be non-recombinant & half the progeny will be recombinant. In this case ratio of non-recombinant & recombinant is 1:1 (as both are 500 numbers). So, they are assorted independently. So, they can be in different chromosomes.
c) Recombination frequency = (No. of recombinant progeny/ Total no. of progeny) x 100%
From the previous q. we know that loci present on the same chromosome in the case of hellbender.
So, their recombination frequency = (200/800) x 100% = 25%
So, recombination frequency of hellbender is 25%.
Phenotype Genotype Offspring No. Type of Progeny Long tail & slimy skin Tt Ss 405 Non-recombinant Short tail & non-slimy skin tt ss 395 Non-recombinant Long tail & non-slimy skin Tt ss 102 Recombinant Short tail & slimy skin tt Ss 98 RecombinantRelated Questions
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