A three point test cross was carried out in Drosophila melanogaster involving three adjacent genes A, B and C. arranged in the same order. The distance between A to B is 15 map unit (mu) and that between B to C is 30 map. The coefficient of coincidence = 0.67. What is the percentage of double recombinants in the progeny obtained from the testcross?

#Question id: 6991

#Unit 5. Developmental Biology

Metamorphosis of amphibians is triggered by environmental cues that act on the:

#Question id: 24213

#Unit 1. Molecules and their Interaction Relevant to Biology

#Question id: 5665

#Unit 5. Developmental Biology

 Following statements are regarding to cortical granule reaction.

A. To initiating the slow block to polyspermy the release of Ca2+ that occurs when the sperm enters the egg is critical for activating the egg’s metabolism and initiating development

B. Calcium ions release the inhibitors from maternally stored messages, allowing these mRNAs to be translated

C. Calcium ions are not release the inhibition of nuclear division, thereby allowing cleavage to occur.

D. Udx1, the enzyme responsible for the reduction of oxygen to crosslink the fertilization envelope, is also NADPH-dependent

E. The fertilization envelope is elevated from the cell membrane by glycosaminoglycans which provides support for the blastomeres during cleavage

Which of the following combinations are correct?

#Question id: 5205

#Unit 11. Evolution and Behavior

Why is it preferable to use large computers and databases in searching for individual genes, rather than testing each sequence for possible function?

#Question id: 13142

#Unit 10. Ecological Principles

The Norway rat (Rattus Norvegicus), a widespread pest, was controlled for about a decade by the anticoagulant warfarin. This chemical substance, placed in food pellets, is absorbed by the intestinal tract and inhibits the clotting of blood. After a population decline for about 10 years, rat populations increased and stabilized. In one European population, as illustrated in the graph below, the percentage of rats resistant to warfarin has remained fairly stable over a number of years.

Resistance to warfarin is governed by a dominant autosomal gene, R. More than 15 percent of the resistant animals are heterozygous at this locus (Rr). The table below indicates the response to warfarin and relative reproductive fitness of individuals that are homozygous or heterozygous for the dominant gene (R). The RR individuals have a 20-fold increase in vitamin K requirement over individuals.