Lecture 17: Evolution of Sex

Question 1

What is asexual reproduction?

Answer 1

genotype maintained

Question 2

What is sexual reproduction?

Answer 2

1. mating of unrelated individuals

2. meiosis and crossing over

Question 3

Define parthenogenesis

Answer 3

A form of asexual reproduction in which growth and development of embryos occur without fertilization

Question 4

Does drift increase or decrease LD?

Answer 4

Drift increases LD

Question 5

Does random mating increase or decrease LD?

Answer 5

Random mating decreases LD

Question 6

Does recombination increase or decrease LD?

Answer 6

Recombination decreases LD

Question 7

What is Muller’s ratchet?

Answer 7

the process by which the genomes of an asexual population accumulate deleterious mutations in an irreversible manner (cannot reduce the number of mutation on a chromosome)

Question 8

What is the advantage sexual reproduction has by generating more genotypes?

Answer 8

More genotypes allow for faster adaptation to varying environments (larger range of genotypes, some offspring genotypes may survive in novel environments)

Question 9

Why is the reduction of LD beneficial?

Answer 9

• Recombines “loaded” chromosomes

- Generates novel genotypes in changing environment

Question 10

By looking at the DNA of a species, how would be no if it makes use of asexual or sexual reproduction?

Answer 10

• Asexual: DNA sequence of alleles should diverge, no genetic exchange
• Sexual: DNA sequence of alleles should be similar, homogenized by genetic exchange