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: 4817

#Unit 8. Inheritance Biology

How many different gametes can be formed by an organism with genotype AaBbCCddEe, If a, b and c gene are completely link?

#Question id: 4819

#Unit 8. Inheritance Biology

Plant with genotype AB/ab is test cross, two genes are linked are 10 map units apart. What proportion of progeny will have the genotype aabb?

#Question id: 4820

#Unit 8. Inheritance Biology

Which of the following gametes are produced in grater proportional by an individual of genotype Ab/aB if the genes are in the same chromosome with some recombination between them?

#Question id: 4821

#Unit 8. Inheritance Biology

What are frequency of recombination  if one cell carry out cross over every 50 cell undergoes meiosis ?

#Question id: 4822

#Unit 8. Inheritance Biology

In a particular species of mammal black hair (B) is dominant to green hair (b) and red eyes (R) are dominant to white eyes (r). If a BbRr individual is mated with a bbrrindividual the expected phenotypic ratio of the offspring is 1 black-red : 1 black-white: 1 green-red : 1 green-white. However, when you mate these individuals you find that the phenotypic ratio of the offspring is 6 black-red :1 black-white : 1 green-red : 6 green-white. What could account for this difference?

#Question id: 4823

#Unit 8. Inheritance Biology

Which one of the following DNA markers can be used to distinguish between a homozygote and heterozygote ?