Population Gentics

Question 1

International HapMap project is?

Answer 1

Finding the more common SNP variants in the worlds population

Question 2

LD blocks are?

Answer 2

Haplotype, linked marker alleles on one chromosome that are inherited together. Tend to remain intact due to short distance, not affected by meiotic recombination
(Linkage disequilibrium blocks)
Unit of inheritance

Question 3

What is the bottleneck effect?

Answer 3

Humans undergo a catastrophic reduction in population new population not as genetically diverse and migrate out of Africa therefore African populations far more genetically diverse than the rest of the world highest number of genetic polymorphisms

Question 4

What is population genetics?

Answer 4

The study of allele frequencies in population gene pools in relation to time (evolution/migration) and space(geography)

Question 5

An example of genetic evidence for evolution in populations

Answer 5

Studying human genome variation reveals evolutionary pressures on haplotypes
The regions low in genetic variation, must have had positive selection for those haplotypes, increasing frequency in population

Question 6

Why have certain haplotypes increased in frequency in the population?

Answer 6

Contain advantageous genes, selection from environment meaning increased fitness, increased offspring, increasing population

Question 7

Genes showing this selective pressure

Answer 7

Pathogen response, reproduction, DNA and protein metabolism
HBB gene for haemoglobin B associated with disease
LCT for lactase for lactose metabolism

Question 8

Mutation in EPAS1:

Answer 8

Detects low oxygen levels and changes physiology

Question 9

Population genetics can lead to optimal medical treatment as we can determine how an individual will respond to a drug based on their genetic makeup

Answer 9

Factors under genetic control:

Inactivation, toxicity, disease mutation type

Question 10

Most common mutation in cystic fibrosis?

Answer 10

Mutation in G551D just damage function of protein, which can be fixed by ivacaftor
But screening patients would cost too much

Question 11

Modern genetic technologies

Answer 11

Genome chips for SNPs and CNV analysis
Some applications:
1.Determining genetic structure of populations
2.snp alleles that have risk of disease or response to/side effects of a drug (GWAS)
3. Determine copy number changes in a population/if they cause disease

Question 12

Sequencing has highlighted

Answer 12

The difference between old common variants and newer rarer geographically restricted variants

Question 13

Population genetics of rare variants has told us:

Answer 13

1. the rarer the variant the more likely it is to be harmful
2. almost 90% harmful ones arose in the past 5000-10000 years before have been weeded out
3. White Europeans have more harmful mutations (less time for weeding out)
4. 50-80% mutations are population specific r