L14: Population Genetics Flashcards
What is population genetics?
Studying genetic variables within & between groups of individuals of the same species
Define a population
A group of individuals belonging to the same species that live in a define geographic area
Define gene pool
All alleles present in a population
5 ways allele frequencies in a population can be altered by
1) Natural selection
2) Mutation
3) Migration
4) Genetic Drift
5) Founder effects & genetic bottlenecks
What are differences between human populations used for?
- Identify how different populations have arisen
- Study genetic differences between populations to identify genes
What does the Hardy-Weinberg Equation describe the relationship between?
Allele frequencies & genotype frequencies in a population under ideal conditinos
5 assumptions of the Hardy Weinberg Equation
1) Large population size
2) Random mating
3) No natural selection
4) No migration
5) No mutation
Equation for a single gene with 2 alleles (A & a)
p+q=1
Hardy Weinberg Equation
p^2 + 2pq + q^2 = 1
What does genetic drift refer to?
Random fluctuations in allele frequencies, especially in small populations
How does genetic drift affect allele frequencies in small populations?
It causes random allele fluctuations, altering genetic variation
When does the founder effect occur?
When a small group of individuals establishes a new population, leading to higher frequencies of certain alleles
What does founder effect + genetic drift result in?
High frequencies of autosomal recessive disorders
Symptoms of the Ellis-Van Oreveld Syndrome
Autosomal recessive skeletal dysplasia characterised by short limbs, short ribs
What is consanguineous mating?
Mating between related individuals
What role does consanguineous mating play in the incidence of inherited genetic disorders?
It increases the likelihood of inheriting recessive alleles
What factors contribute to the high incidence of genetic disorders in the Old Order Amish population?
The founder effect and genetic drift
What are autosomal recessive disorders, and how do they differ from dominant disorders?
They require two mutated gene copies, while dominant disorders need only one
When does genetic bottlenecks occur?
Occurs when a large population is significantly reduced in size by natural disaster
Define phylogenetics
Study of evolutionary relationships using DNA sequences
What is complete achromatopsia?
Total colour-blindness & difficulty seeing in daylight
Does closely related species have more SIMILAR/DIFFERENT DNA sequences?
similar
Does distantly related species have more SIMILAR/DIFFERENT DNA sequences?
different
How does the structure of a phylogenetic tree represent relationships among Y-chromosomal haplogroups?
It illustrates evolutionary relationships inferred from shared SNPs
What is the importance of screening cancer patients for mutated genes?
To inform treatment decisions based on the mutated genes
What is phenylketonuria (PKU), and how is it treated?
A genetic metabolic condition impacting phenylalanine processing, managed via dietary restriction
How do phylogenetic trees help in understanding human evolution?
By illustrating genetic relationships and migration patterns
What is the relevance of studying Y-chromosome haplogroups in understanding human ancestry?
They help trace paternal lineages and understand the relationships between human populations
How can the Hardy-Weinberg law be used to calculate genotype frequencies?
Based on allele frequencies using the equation p^2 + 2pq + q^2 = 1
What are Y haplogroups and what do they indicate about human migration?
Branches of the Y-chromosome tree defined by SNPs, tracing human migration routes
How does migration influence the gene pool of a population?
It introduces or removes alleles in the population
What advancements in genomic medicine are expected to improve patient diagnosis and treatment outcomes?
Tailored screening based on individual genetic profiles
What does the term “evolutionary clock” refer to in the context of DNA changes?
The accumulation of DNA changes at a constant rate over time
The accumulation of DNA changes at a constant rate over time
Sharp reduction in population size leading to a loss of genetic diversity
What is the aim of the NHS Genomic Medicine Service regarding whole genome sequencing?
To offer whole genome sequencing as part of routine care
What is the role of mutation in creating new alleles within a population?
Mutation introduces new alleles into a population
How does non-random mating lead to an increase in genetic diseases caused by recessive alleles?
It increases homozygous pairings for recessive alleles
