Sexual reproduction increases genetic variation in a population. Which is a way that meiosis and
fertilization lead to genetic variation? (4.5) *
(5 Points)
Alleles are recombined when gametes from different parents join together.
Mutations are usually repaired by cellular machinery before genes are expressed.
DNA is replicated when a fertilized egg becomes a growing embryo through mitosis.
Parents that are homozygous for the same trait will have offspring that are also homozygous for that trait.

Alleles are recombined when gametes from different parents join together.

Explanation:

Genetic variation is increased by sexual reproduction in 3 main ways

1. Random mating - individual organisms reproduce with each other at random, meaning new combinations of DNA come together when fertilization occurs

2. Crossing over - during meiosis, when homologous chromosomes align, they can exchange genetic material by a process called crossing over, or homologous recombination. This means the alleles on each homologous chromosome are reshuffled, creating new combinations.

3. Independent assortment - When gametes are formed, a diploid cell duplicates its DNA and forms 4 haploid cells. Each of the homologous pair of chromosomes in the diploid align in the centre of the cell to be split into the gametes at each division. The orientation at which they line up is random, so every gamete gets a different selection of chromosomes (which themselves have been shuffled bt crossing over).

Only the 1st option (Alleles are recombined when gametes from different parents join together.) is correct. This represents the process of random mating, where new combinations of alleles are formed during fertilization between two individuals.