28. In mammals effective dosage of genes of two sexes is made equal by- (1) Elimination of X chromosome in females (2) Hyper activation of one X chromosome in males […]
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DNA Methylation as the Mechanism of X Chromosome Inactivation in Human Females
27. In human females there is inactivation of one X chromosomes for dosage compensation due to- (1) Methylation (2) Acetylation (3) Phosphorylation (4) Formylation In human females, X chromosome inactivation […]
Complementary Gene Interaction in Plants
26. In a plant r+ and a+ genes encode for a regulatory and a structural protein, respectively. These genes are responsible for blue color of flower. Mutation in either of […]
Genetic Inheritance of Fruit Shape in Plants
25. A plant that produces disc-shaped fruit is crossed with another plant that produces long fruit. All the F1 plants gave disc-shaped fruits. When the F1 were intercrossed, F2 progeny […]
Epistasis in Mammalian Coat Colour
24. In a mammal, coat colour is governed by gene B, The coat colour is either black or brown, depending on whether the genotype is BB or Bb. It is […]
Genetic Explanation of 6:2:3:1 Phenotypic Ratio in Mice Crosses with Recessive Lethal Alleles
23. Two Yellow mice with straight hair were crossed and the following progeny was obtained: 1/2 Yellow, straight hair 1/6 Yellow, fuzzy hair 1/4 gray, straight hair 1/12 gray, fuzzy […]
Interpreting epistasis and gene interactions in flower color loci
22. In a flower species, light pink locus is hypostatic to pigment development locus. R is for pigment development and W for light pink. The recessive allele (w) in light […]
Epistasis in Insect Eye Colour
21. The following is a hypothetical pathway for the development of wild type (red) eye colour in an insect: Enzymes A and B are encoded by the genes a+ and […]
Linked genes eye colour problem
20. The following is a schematic representation of a hypothetical pathway involved in formation of eye color in an insect species. Genes A and B are linked and have a […]
Hypothetical biochemical pathway
19. A hypothetical biochemical pathway for the formation of eye color in insect is given below. Two autosomal recessive mutants ‘a’ and ‘b’ are identified which block the pathway as […]


