a. What are molecular genetic markers? Provide 2 examples. b. Give two examples

Question

a. What are molecular genetic markers? Provide 2 examples.

b. Give two examples of traits that can specifically benefit from marker assisted selection

c. Define the terms ‘Deme’ and ‘Selection pressure’ as they relate to evolution.

d. Differentiate between pleiotropy and polygenic inheritance.

e. Differentiate between Selection criteria and Breeding Objectives.

f. The bonus in value of a trait obtained from a cross, which is over and above that of the average effect of the parents, is, (1 or 2 words)?

g. Write the formula for calculation of ‘effective population size’ and briefly describe why it may be different for breeding populations with exactly the same number of animals in them.

Explanation / Answer

Ans a) The molecular genetic markers are fragments of DNA that are located within certain location within the genome. They have a huge impact on biology and molecular biology as it helps on identifying a particular sequence of DNA from a huge pool of DNA. Two example of genetic markers are restriction fragment length polymorphism (RFLP) and randomly amplified polymorphic DNA (RAPD)

Ans b) The MAS (Marker assisted selection) is a process where trait of interest is selected based on the marker used or linked to that particular trait of interest. Two examples of traits that can be considered here are traits for disease resistance and abiotic stress tolerance trait.

Ans c) Deme is a local population that categorizes the polytypic species which are able to actively inbreed with one another and this helps them to share a good and distinct gene pool. The deme are great for evolutionary studies as when they are isolated for a very long time, they tend to become sub species of main species. The selection pressure is external agents or factors which affect the ability of the organisms to survive in a given environment. It can be both negative and positive where in the former it decreases the trait occurrence and in the positive it increases the trait proportion.

Ans d) Pleiotropy – It is the condition when one gene is responsible for regulating or influencing many phenotypic traits or characteristics. In case of polygenic inheritance, it is one trait which is controlled by many genes.

Ans e) The selection criteria is the ability of some individual to survive and reproduce with certain genotypes while other eliminate. This preference is done by means of natural or outside or artificial factors. The breeding objective is to improve the yield of the plants in case of forages that includes higher yield, quality, resistance to pests and better tolerance towards climatic conditions. In case of animals, it is better qualities and survival.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.