Molecular Evolution

Question 1

define evolution, natural selection and fitness

Answer 1

12

Question 2

Describe the modern synthesis of genetics and evolution with respect to the frequencies of genetics variants

Answer 2

Selection: genetic variants which are advantageous will be selected to increase inheritance of traits by offspring

Mutation: how variation in genome is formed

Migration: movement of species introduced into another existing population = new variants formed from ‘admixture’

Genetic Drift: - selection pressures
frequency of variant altered by chance over time
- recombination and deleterious traits drive drift
- selection pressures negate it

Question 3

Describe sequence conservation, where specific levels of conservation occur in genes and what we can use it for

Answer 3

> What is sequence conservation?
to protect vital sequences which ensure functional integrity (required in all cells )
Analysis can be done to see level of conservation
High: present in coding regions
Intermediate: present in exon - promoter, 5’UTR 3’UTR, terminator
Low: intron, 3rd base of codon (due to multiple codons = 1 amino acid) + terminator
What applications does sequence conservation

Question 4

Describe the basis aspects of phylogenetics, what a phylogenetic tree is and how it can be used

Answer 4

phylogenetic tree tracks relatedness of species using time distance
less divergence = closely related

Question 5

Describe processes of molecular evolution with respect to the globin gene clusters

Answer 5

Globin gene clusters:
- zeta, echelon chains are embryonic and fade during 6-8 weeks of gestation
- gamma chain (foetal) increases expression through birth and drops within 3-6 weeks.
- alpha chain remains constant
- beta chain (shows most divergence) crossover gamma 3-6 weeks postnatal
-HbS mutation in position 6

Question 6

Describe what a pseudogene is

Answer 6

pseudogene: non functioning gene, many located in genome, with some diverging after duplication