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 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 dominant 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: 3634

#Unit 8. Inheritance Biology

In the pearl millet plant, color is determined by three alleles at a single locus: Rp1 (red), Rp2 (purple), and Rp3 (green). Red is dominant over purple and green, and purple is dominant over green (Rp1 >Rp2 >Rp3). Which of the following parental cross would produce ½ had red, ¼ purple, ¼ green?

#Question id: 3635

#Unit 8. Inheritance Biology

In the multiple allele series that determines coat color in rabbits, c+codes for agouti, cch for chinchilla and ch for Himalayan. Dominance is in the order c+>cch>ch. In a cross of c+/cch X cch/ch, what proportion of progeny will be chinchilla?

#Question id: 3636

#Unit 8. Inheritance Biology

A man with type A blood group marries a woman with type A blood group. Their first child has type O blood. What is the genotype of the Man, proportion of his gametes are expected to contain the IA allele, and probability that their next child will have type A blood respectively:

#Question id: 3637

#Unit 8. Inheritance Biology

Parents that are homozygous for different mutations a, b and c are crossed, producing offspring that are heterozygous as following

aa X bb        =  ab  (X)          

 bb X cc         =  bc  (Y)

aa X cc          =   ac  (Z)

If a and b belong to same locus but b and c belong to different locus then phenotype of heterozygote

#Question id: 3638

#Unit 8. Inheritance Biology

Four different mutant lines showing similar phenotype were identified from a genetic screen. When genetic crosses among these mutants were carried out, the first mutant was found to complement the second, third and fourth mutant lines. However, no other complementation groups do the four mutant lines belongs to?

#Question id: 3639

#Unit 3. Fundamental Processes

Replication of a bacterial chromosome normally starts at a fixed point called: