population genetics Flashcards
What is the study of the statistical distribution of genes to better understand disease frequencies within different populations?
Population genetics
What is one of the first identified beneficial mutation and what disease does it protect against?
CCR5 and HIV Resistance - Homozygotes have defective surface receptor that the HIV virus needs to enter and infect cells, making them immune to AIDS (still test pos for HIV, just never develop full-blown AIDS)
What does the Hardy-Weinberg Equation describe
Describes allelic and genotypic frequencies in populations
What assumptions are made for Hardy-Weinberg?
i. Random mating
ii. Large population size
iii. No mutations
iv. No migration/genetic drift = no new alleles introduced/lost
v. No natural selection
What is the Hardy Weinberg equation
p2 + 2pq + q2 = 1
p + q = 1
P = dominant alleles
q = recessive alleles
Unaffected individuals = p2 + 2pq
For rare or typically lethal recessive traits - p ~ 1, meaning 2pq roughly equals 2q
- number of heterozygotes outnumbers affected individuals
What are types of Nonrandom mating in which humans violate hardy weinberg?
Stratification, Assortive Mating, Consanguinity, Inbreeding
What is it called when subgroups are genetically separate from a population and will only breed amongst themselves
Stratification (i.e. Ashkenazi Jews, Cajuns)
What is it called when you choose mate based on possessing a particular trait (dwarfism and deafness
Assortive mating
What is it called when gene frequencies become randomized (not controlled by natural selection)
Genetic Drift
What is caused by an event that greatly reduces population size, what does it change
Bottleneck effect ; randomly changing allelic frequencies
What is the Founder effect? what can it occur after
starting population size is very small, reducing genetic variation, allelic frequencies drift to predominantly one particular allele for a give trait
- bottleneck event
What is the term for when new genes are introduced to a population change allelic frequencies (via travel, etc.)
Gene flow (migration)
What Looks at the entire genome to identify genetic associations with observable traits and differences in genome within and between population? What are the uses?
Genome Wide Association Studies; increased understanding of basic biological processes affecting human health, improvement in the prediction of disease and patient care, and ultimately the realization of personalized medicine.
What is cataloged in a HapMap what will it identify?
SNPs single nucleotide polymorphisms; identifying subsets of individuals at risk for specific diseases
What are Copy number variants? what are they caused by?
gene duplications/deletions cause an abnormal number of copies of a particular gene in their genome (not always a deleterious variation). This can greatly affect the expressivity of a certain condition.
A. Can be caused by SNPs, insertions, deletions, nucleotide repeats, and gene repeats
B. Suspected to underlie genetic diversity and disease susceptibility
