Lecture 13- 10/18

Question 1

SNPs

Answer 1

single nucleotide polymorphisms

- can be used for mapping genes and studying human evolution, used as markers

Question 2

the causes of genetic variation

Answer 2

• ultimate cause is mutation
  1. overdominant selection
  2. mutation drift balance: usually main control, genetic drift removes variation, can maintain high levels of polymorphism
  3. Mutation Selection balance
• can only explain very little variation

Question 3

speciation

Answer 3

the process of generating new species

• different species are reproductively isolated
• prevention of gene flow causes speciation= most likely geographic isolation

Question 4

prezygotic reproductive isolation

Answer 4

Geographic or ecological
Seasonal or temporal
Behavioral
Mechanical
Physiological

Question 5

postzygotic reproductive isolation

Answer 5

Hybrid nonviability
Hybrid sterility
F2 breakdown= zygote of F1 is fine, F2 cannot reproduce

Question 6

min genetic divergence required for speciation

Answer 6

• possibly 1 gene
• likely 2 genes

need at least two genetic changes