Question

a) Describe, in detail, how a genetic cross can be used to identify the number of genes involved in major changes in body form between two different organisms.

b) If you found a group of similar species living on nearby islands, describe in detail a method you could use to determine their exact evolutionary relationship to each other.

c) Describe, in detail, how a mutation in the intracellular domain of MC1R could change the coat color in rock pocket from light to dark.

d) Besides looking for microfossils, describe another test you could perform on rocks from 3-4 billion years ago to find evidence that life existed at that time?

Answer 1

a) The number of genes invoved in the major changes in the body form between two different organisms can be identified by observing the different traits that are expressed by the concerned gene related to a particular characteristic. For example, a mouse population has two coat colors, this denotes that this is affected by two alleles of a gene. For this, a test cross can be performed and the phenotypic traits of the progeny can be onserved.

b) The group of similar species living on the nearby island can be evolutionary related to the original group by identifying the homologus groups of genes and characteristics between them. The more the homologus features, the more closely they are related.

c) The mutation in the intracellular domain of the MC1R gene results in the change in the structure and function of the related protein, which is resoponsible for the production of emulenin. The changes in the protein results in an increased released of emulenin, which leads to dark fur coat color.

d) The rrocks could be tested for thepresence of organisms to find an evidence that life existed at that time.