6.1.5 Genetic Variation

Question 1

Fertilisation

Answer 1

Involves the combination of gametes to form a zygote

• The alleles for each gene in the gametes to be independently assorted and segregated in meiosis

Question 2

Variation through Meiosis

Answer 2

1. Crossing Over - pieces of sister chromatids are switched
2. Independent Assortment - chromosomes line up randomly
3. Random Segregation - spindle fibres attach randomly to chromosomes and separate

This means that variation occurs through the replication of DNA or separation of chromosomes.

Question 3

Variability increases through…

Answer 3

• Recombination - Meiosis and fertilisation allow for variation through gamete formation and fusion.
• Alleles - Mutation increases the number of alleles for a particular trait.