BIO-0013 Lecture : 11-1-12.docx

The syntenic genes A and Z are linked. A cross between two parents, AAzz and aaZZ, produces F₁ progeny with the AaZz genotype. What are the possible arrangements of alleles on the F₁ progeny's chromosomes?

The answer is not AZ/az

Genes that are on the same chromosome can assort independently when

Genes that are on the same chromosome can assort independently when

Please help me with these two!

Question:

If a female animal with genotype A/A. b/b (the back-slash indicates the chromosome) is crossed with a male that is genotypically a/a. B/B and the F1 is testcrossed, determine the percentage of the progeny from the testcross that will be a/a. b/b, if the two genes are:

a. Unlinked (Show your work).

Answer: AaBb X aabb AaBb – ¼ aabb - ¼ aaBb - ¼ Aabb - ¼ OK

b. Completely linked, i.e., no crossing over at all (Show your work).

Answer: With completely linked genes without crossing over, the only genes possible are AB and ab gametes.

Result:

Therefore the only possibility of having homozygous aabb is 50%.

No; a b is recombinant; please redo

c. 10 mp units apart (Show your work).

Answer: If the linked genes are 10 map units apart, 10% of the results would be recombinants. As F1 progeny ab is part of the parental class, only half of the total parental genotypes will be present. Therefore: 45%

No; a b is recombinant; please redo

d. 24 map units apart (Show your work).

Answer: Same rule applies for c. Therefore the percentage of progeny would be equal to 38%.

No; a b is recombinant; please redo

This is all the information given and need help. I've answered the question and my prof says the answers for b c and d are wrong. Could you please help me out? and also could you explain with the answers? Thank you.