Flashcards in Population Genetics Deck (101)
Define population genetics
The study of diversity within and across populations along with its causes and implications
What is population genetics required for?
For establishing the evolutionary relationships between populations and thus, human population diversity.
What 5 things does population genetics incorporate?
Migration patterns (local, regional, global), relatedness of different populations, mating patterns, admixture, natural selection
What is admixture?
Genetic admixture occurs when individuals from two or more previously separated populations begin interbreeding.
What are the consequences of admixture?
Admixture results in the introduction of new genetic lineages into a populations..
How does admixture affect adaptation?
Admixture slows down local adaptation by introducing foreign, unadapted genotypes (gene swamping). It also prevents speciation by homogenizing populations.
T/F: Gene frequencies for traits/ diseases may be present in different freqeucnies within populations.
What does population genetics enable us to do?
To map susceptibility factors of a disease onto the genome and offers advantages in genetic counselling and forensics.
What three factors influence genetic diversity?
Genetic mechanisms, evolutionary forces, population characteristics.
What are the genetic mechanisms influencing genetic diversity?
Mutation and recombination
What are the evolutionary forces influencing genetic diversity?
Natural selection and genetic drift
What are the population characteristics?
Population size, geographic distribution, mating patterns and migration.
Where is the A allele predominantly distributed?
Where is the B allele predominantly distributed?
There is a block of high distribution extending from northern central Russia to the Indian subcontinent.
Where is the O allele predominantly distributed?
South America, central America
How was the distribution of the ABO alleles discovered?
Using genetic markers which are loci that are frequently heterozygous in a population.
What is the MAF of genetic markers?
How can maternal lineage be traced?
Through using mtDNA
How can paternal lineage be traced?
Through Y-chromosome haplotype
T/F mtDNA is linear
How many genes are found on mtDNA?
37 genes, required for normal mitochondrial function.
13 mitochondrial genes encode for...
enzymes involved in oxidative phosphorylation
Why is mtDNA exclusively inherited maternally?
All spermatozoan mitochondria are metabolised upon fertilisation of the oocyte.
T/F: the majority of mtDNA is non-coding
False; the majority is coding, however the non-coding region has a high mutation rate and does not recombine.
How can mtDNA be used in gene mapping?
The high mutation rate and lack of recombination result in these mutations accumulating on the haplotype, thus enabling related haplotypes to form haplogroyps
What are haplogroups?
These are groups of mutations found on mtDNA which share defining variants at key sites.
T/F: The Y chromosome recombines with the X chromosome
Neither; only the telomeric pseudoautosomal regions recombine with the X chromosome.
Why is the Y chromosome male specific?
The Y chromosome is the chromosomal determinant of males in humans, as their sex chromosomes are XY.
What can mtDNA and Y chromosome haplogroups be used for?
To reconstruct the relationship among haplotypes through using mutations. The geographic distribution of lineages can then provide information on the history of populations such as population origin, population age.