In this problem we will explore some of the many ways that mutations in two different genes can interact to produce different Mendelian ratios. Consider a hypothetical insect species that has red eyes. Imagine mutations in two different unlinked genes that can, in certain combinations, block the formation of red eye pigment yielding mutants with white eyes. In principle, there are two different possible arrangements for two biochemical steps responsible for the formation of red eye pigment. The two genes might act in series such that a mutation in either gene would block the formation of red pigment. Alternatively, the two genes could act in parallel such that mutations in both genes would be required to block the formation of red pigment.

Further complexity arises from the possibility that mutations in either gene that lead to a block in enzymatic activity could be either dominant or recessive. If the crosses is made between a wild type insect with red eyes and a true breeding white eyed strain with mutations in both genes. Such considerations yield the Pathways in parallel with recessive mutations in both genes, determine the phenotype of the F1 progeny and the expected phenotypic ratio of red to white eyed insects in the F2.

#Question id: 4865

#Unit 8. Inheritance Biology

Neurospora strain with genotype Ab was cross to another strain with genotype aB. Following different ascus and their appropriate number given in table.

Which is distance between gene A and Gene B?

#Question id: 4866

#Unit 8. Inheritance Biology

In a certain diploid plant, the three loci A, B, and C are linked as follows: Assuming 100%   interference, if the plant with genotype ABC/abc is test cross, what proportion of the progeny will be of the genotype a b c/a b c?

#Question id: 4867

#Unit 8. Inheritance Biology

A three point test cross was carried out in Drosophila melanogaster involving three adjacent incomplete link genes A, B and C. arranged in the same order. The distance between A to B is 5 map units (mu) and that between B to C is 10 map. If pure line Drosophila AAbbCC crosses with aaBBcc to produce F1 offspring were allowed to cross with aabbcc result in following offspring genotype?

What is a A, B, C respectively?

#Question id: 4868

#Unit 8. Inheritance Biology

 A mouse cross C/c . D/d X c/c . d/d is made, and in the progeny there are

45% C/c . d/d, 45% c/c . D/d,

5% c/c . d/d, 5% C/c . D/d

What are distance between C and D gene?

#Question id: 4869

#Unit 8. Inheritance Biology

In the plant Arabidopsis, the loci for pod length (L, long; l, short) and fruit hairs (H, hairy; h, smooth) are linked 16 map units apart on the same chromosome. The following crosses were made:

(i) L H/L H X l h/l h = F1

(ii) L h/L h X l H/l H = F1

If the F1’s from (i) and (ii) are crossed, what proportion of the progeny are expected to l h/l h?

#Question id: 4870

#Unit 8. Inheritance Biology

Following gene order is for three points. If Genotype +y +ct +v produced actual number of double cross over gamete is 10 out of total 1000. What is interference value?