Flashcards in Lecture 1 - What is population genetics Deck (18)
a varient of a gene (or more generally of a genetic locus)
Why doe understanding micro-evolutionary process matter?
-genetic mapping of disease
Breeding of domestic plants and animals
How is population genetics studied?
Historically - was a theory rich and data por subject
Now - data rich due to more powerful molecular methods, but theory needed to make sense of the data
What is evolution
A change of allele freguencies in a population
What are the four key processes involved in evolution? (In order to change allele frequencies)
Gene flow between populations
(all act together in thre real world)
What are the features of mutation?
-all genetic variation occurs by mutation
-increases genetic diversity
-very low frequency
What are the features of genetic drift?
-random changes in allele frequency from one generation to the next
-reduces genetic diversity
-important in small populations (where there is not much allele diversity)
What are the features of selection?
-Acts on fitness differences of genotypes (requires phenotype variation with a genetic basis)
-Leads to adaptation
-usually reduces genetic variation, however disruptive selection increases genetic variation
What are the features of gene flow?
-depends on the structure of a population e.g. Migration: reduces divergence between populations
-can restore some genetic variability
a visible or measurable trait or series of traits in an individual
the combination of alleles at a genetic locus or set of loci in an individual
Define Genetic locus
a stretch of DNA in the genome
a stretch of DNA coding for a protein or functional RNA
What is mendels first law?
-individuals have a pair of alleles for a given trait and these segregate separately into gametes
-one allele is passed on randomly from each parent to their offspring
P1: Yellow and Green
F1: 100% yellow
F2: 3/4 Yellow, 1/4 Green
F3: 1/4 Yellow F2 (YY) -> 100% Yellow
-2/4 Yellow (Yy) -> 3/4 Yellow, 1/4 green
-1/4 Green (yy) -> 100% Green
What is a dominant allele?
An allele is dominant when the associated phenotype is expressed in the homozygous or heterozygous state
What is a recessive allele?
An allele is recessive when the associated phenotype is only expressed in the homozygous state
What is a co-dominant allele?
Alleles are co dominant when the heterozygotes have an intermediate