Assignment: Make a Genetics Homework Problem. Create a genetic mapping homework

Question

Assignment: Make a Genetics Homework Problem. Create a genetic mapping homework problem. (Examples are questions 1, 2, and 3 in the Topic 19 study questions.) In the problem you create, the student is given the results of a testcross involving two of the genes on the map at the right and is asked to determine the recombination frequency. In other words, pick two linked genes from the map of the Drosophila X chromosome at the right and make up data for a test cross so that when the student calculates the recombination frequency they get the same distance as given on this map. How to use the genetic map The diagram to the right is a genetic map of the Drosophila X chromosome. It shows the positions of genes along the chromosome and the units are centimorgans (100 x phi). To find the distance between two genes, subtract their map positions. For example if gene p was at position 65.5 and gene n was at position 59 then the distance between them is 65.5-59 = 6.5 cM. That means that you should expect to see a recombination frequency phi = 0.065 On this map, if the mutant allele is recessive to wild type, it's symbol is made with lowercase letters. If the mutant allele is dominant to wild type, the gene symbol is made with capital letters. The only gene on this map where the mutant is dominant to wild type is Bar eyes. Note that these genes are all X-linked. That will affect how you do the cross and interpret the data. In a mapping testcross, the F_1 generation must be heterozygous for both genes, but only females have the possibility of being heterozygous because they have two X chromosomes Prepare your question, as well as the correct answer, as a Word document or pdf and upload it by the deadline.

Explanation / Answer

ANSWER-

The figure shows the Mapping of X-chromosome of Drosophilla gene, where all the genes are maped with position/location.

Test cross is the genetic cross between a homozygous recessive individual and a corresponding suspected heterozygote to determine the genotype of the heterozygote.

Here if we take the example of "fuged vains"- fu and scalloped wings -sd,

The distance between two genes is- 59.5 - 51.5 = 8.

That is the distance between the two gene is 8cM. Hence the recombinant frequency () will be 8/100 = 0.08

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