8/26/14 - Genetic Variation in Individuals & Populations Flashcards
(34 cards)
What is the founder effect?
When a small subpopulation with a different allele distribution breaks away from the general population
What is aneuploidy?
An abnormal number of chromosomes.
Why are point mutations often paternally inherited?
Since spermatogonium undergo repeated mitotic division, they are more prone to replication errors, the most common being point mutations.
What diseases are typically associated with MHC molecules?
Autoimmune
What is a classic case of a balanced polymorphism?
Sick cell heterozygosity confering resistance to malaria.
An autosomal recessive disease is found in 2% of the population. Calculate the percentage of disease carriers in the same population. (draw)
Heterozygote carriers: 24%
What is a haplotype?
A cluster of linked genes. Due to their close proximity, linked genes are almost always inherited together.
What germline mutations are more likely to occur in women?
Frequency of nondisjunction causing trisomies and large deletions increases with age.
What are the characteristics of the A and B blood types?
Dominant
What is the difference between a point mutation and a SNP?
SNP is a polymorphism, which means it has to be present in >1% of the population.
If a disease confers 40% fitness, what percentage of individuals in that population are able to procreate?
40%
What is a copy number polymorphism?
An abnormal number of gene copies.
What five main factors affect the rate of germline mutation development?
Gene size Presence of CG sequences Mutation phenotype Parental age Parental gender
What is a balanced polymorphism?
Forces exist to both remove and maintain polymorphisms from a population, favoring the heterozygote form.
What germline mutations are more likely to occur in men?
Point mutations
What is a VNTR?
Variable number tandem repeats
What are the characteristics of the AB blood type?
Co-dominant, universal recipient
What are the characteristics of MHC I molecules?
MHC I molecules are expressed on all nucleated cells and residue on cell surfaces. They present protein fragments from within the cell - called epitopes - to immune cells. If the immune cells recognize these epitopes, they will initiate an immune response against that cell.
What is gene flow?
Process by which genes diffuse in a foreign population over time.
What is genetic drift?
Changes with the environment favoring a genetically defined subpopulation
Why are large chromosome deletions more often maternally inherited?
Large deletions more likely due to unequal crossing over during oocyte development.
What is fitness?
The ability to procreate
Why are most people Rh+?
Resus factor expression (Rh+) is a dominant trait, so an individual will need two Rh- alleles to be Rh-.
Hardy-Weinberg equilibrium for 2 alleles (3 genotypes)
Frequency = P^2 + 2PQ + Q^2
