Question

Give two reasons for the appearance of variations among the progeny formed by sexual reproduction.

Answer 1

Various reasons leading to genetic variations from sexual reproduction are:

1. The first major reason is the crossover of homologous chromosomes, which occurs in the pachytene stage of prophase-1 (homologous recombination stage) in meiosis-1 (reductional cell division), generates a recombinant variation in the offspring's DNA.
2. The second major reason is that sexual reproduction involves two parents producing offspring. Hence the variability in the offspring is due to the diverse set of genes of the mother and father.
3. Sexual reproduction causes more viable variations in the offspring as the process of DNA replication is error-prone.
4. The variations arising during the genetic replication process get accumulated in the gene pool over generations, hence rendering the process of genetic variation.
5. The process of natural selection also plays a role in genetic variation, which is based on the survival of the fittest.