Question

Which processes associated with meiosis ensure genetic diversity in offspring? Name two processes that promote variation and explain how they operate.

Answer 1

(a) The processes associated with meiosis that ensure genetic diversity in offsprings are:

i. Crossing over:

Cross over results in an exchange of chromosome segments and mixture of genes and takes place during meiosis I.

ii. Random segregation:

The distribution of chromosomes among the gametes takes place independently and referred to as random segregation.

iii. Independent assortment:

It is the process in which the two homologous chromosomes of a pair must go into separate gametes. This results in each pair sorting its maternal and paternal homologs into daughter cells independently.

(b) Sexual reproduction and mutation are the two processes that promote variation.

Sexual reproduction involves the process of crossing over during meiosis where the exchange of chromosome pieces takes place. This allows mixing of genetic information from the two parents producing offsprings which are different, thus leading to variation.

Mutation is any change in the DNA sequences, can be inherited and creates new traits that are introduced into the gene pool. Mutations lead to genetic variation by producing random changes in an organism's genetic code resulting in a completely different protein, a non functional protein or no protein at all.

The mutated protein may have a negative effect such that the organism cannot perform essential functions. Example: Defect in a metabolic pathway due to an altered enzyme.

It may also have a positive effect (beneficial mutation) which allows a survival advantage to the organism.