Week 4- Population genetics Flashcards
what is population genetics
application of genetic principles to entire populations of organisms
why is there genetic composition and changes in population genetics
natural selection etc
what is a population
group of organisms of the same species living in the same geographical area
what is a subpopulation
any of the breeding groups within a population among which migration is restricted
what does a gene pool consist of
all the alleles for all loci in a population
when is a locus fixed
if all individuals in a population are homozygous for the same allele
what is hardy Weinberg equilibrium
a type of model used by biologists to study populations
what does Hardy-Weinberg equilibrium state
the genotype frequencies in a population remain constant between generations in the absence of disturbances by outside factors
what is Hardy-Weinberg equilibrium used to estimate
the number of homozygous and heterozygous variant carriers of a gene based on its allele frequency in populations that are not evolving
what is Hardy-Weinberg equilibrium used for
to describe a non-evolving population
what are the 5 conditions for genotype frequencies to stay the same
- large population size
- no migration
- no net mutations
- random mating
- no natural selection
how many genotypes are at a locus for a diploid organism
3: Aa, AA, aa
what is the frequency of all genotypes in a whole population
1
what is the Hardy-Weinberg equilibrium equation
p2 + 2pq + q2 = 1
1 = p + q
what does P= ?
Frequency of the dominant allele
what does q= ?
frequency at the recessive allele
what is p2
frequency of homozygous dominant genotype
what is q2
frequency of homozygous recessive genotype
what is 2pq
frequency of heterozygous genotype
how is allele frequency calculated
number of copies of a specific allele in a population / total number of all alleles of that gene in a population
how is genotype frequency calculated
number of individuals with a particular genotype in a population / total number of individuals in a population
what test can be used to check whether deviation is larger than expected by chance
chi-square test
what are Y chromosomes
patrilineal
what are the two types of genetic markers of Y chromosomes
- Y-STRs
- Y-SNPs
what is mtDNA
matrilineal
what is typically sequenced
control region of the mtDNA
what is the haplogroup assigned by
the presence of specific DNA mutations
what is SNP
single nucleotide polymorphism
what is a haplotype
can refer to a combination of alleles or set of SNPs
what is haplogroup
group of people who share a common ancestor on the patriline or matriline
what has driven evolutionary change
- viruses
- positive natural selection
what is 8% of the human genome compromised of
retroviruses at various stages of fossilisation
what is retroviruses at various stages of fossilisation
- non-coding DNA
- Human endogenous retrovirus
what is human endogenous retroviruses
Endogenous viral elements in the genome that closely resemble and can be derived from retroviruses
why are hERVs incapable of replication and contain major deletion or nonsense mutations
because they are merely traces of original viruses, having first integrated millions of years ago
what is syncytin
domestication of a retroviral envelope gene env
what does syncytin do
mediate nutrient transfer from the to the developing embryo in placental mammals
why do all infants have a high lactase enzyme activity
to digest the sugar lactose in milk
when does lactase enzyme activity decline in most humans
after weaning
which genes can become resistant to malaria
- haemoglobin
- enzymopathies
- RBC antigens
- immune genes
how does haemoglobin become resistant to malaria
inherited disorders of HB structure and function
what variants are present at substantial frequencies in any population, in the HbB gene
S, C, E
what does S variant lead to
sickle cell anaemia
what does C variant lead to
?
what does E variant lead to
lover levels of HbB and mRNA
