Population Genetics Flashcards
What is the biological definition of evaluating?
Mutation ———————author
Natural Selection———-editor
Genetic drift ——————the randomizer
Gene flow———————-the homogenizer
The definition of population genetics ?
1-Mathematical Aspects Of Genetics
How genes are distributed & maintained
at particular frequencies in populations
2- study genetic variation within a gene pool and how such
variations change from one generation to the next.
The definition of gene pool ? How we can contribute them ?
1- All alleles in a population
2- total of all genes within the population or locus.
Contribute to gene pool by reproducing.
Definition of population and local population ?
group of individuals same species.
small groups of the population determined by a geographical feature
Definition of polymorphism, monomorphic and single nucleotide polymorphism?.
Polymorphisms: variation of traits influence phenotype
presence of a gene with multiple alleles (genetic variation, more
than one allele).
Monomorphic: single allele
Single-nucleotide polymorphism: commonest and smallest. SNPs
is a substitution of a single nucleotide at a specific position in the genome, that is present in a sufficiently large fraction of the population
How many allele the locus and individual have?
Locus more than 2 alleles
Individual only 2 alleles
What population genetics want to understand ?.
1-Why dominant trait does not increase at the expense of a recessive one
2-How carrier frequency can be calculated knowing the disease incidence
3-Why particular genetic disorder more common in one population than another?
Genetic structure describes…………..and …………..?
Allele and phenotype frequencies
What is the equation of for genetic equilibrium?
Meaning of p / q ?.
P^+2pq+q^=1
P= dominant allele (represented here by A)
q= recessive allele ( represented here by a)
Who put the genetic equation?.
HARDY-WEINBERG LAW
Allele frequencies measure ……….while genotype frequencies shows ……….. and both describe ……..?
genetic variation
distributed
population’s genetic structure.
When dose the allele frequencies change ?.
Mutation , migration and selection
The conditions to be met for a population to be hardy Weinberg equilibrium-are ?.
1- mating is random 2- Population size is very large. 3- no migration 4-no mutation. 5-Natural selection does not affect the alleles
What happen if we make ideal condition for the population?
1- The frequencies of alleles at a locus will
constant from generation to generation.
2- genotype frequencies will not change
The type of the disease PKU ? What the results of it ?
autosomal recessive metabolic disorder
mental retardation if untreated during the newborn
period.
Why it is useful to use HARDY-WEINBERG EQUATION
Even if it is impossible to the conditions it’s need ?.
1- predicting genotype frequencies from allele
frequencies
2- help identify specific mechanisms of evolution
3- prompt a search for factors that cause the-deviation
e.G. Heterozygote advantage
HARDY-WEINBERG -uses are ?
1- assumed populations in
equilibrium for most genetic traits (unless there is evidence to the contrary)
2- Carrier frequencies of an autosomal recessive disorder
3- Important for genetic counselling
Method of calculating carrier frequencies?
جذر Disease incidence
اطلع منه p
2pq
================+========================
doubling the square root of the disease
incidence i.e. 2 x 1/100
Factors Disrupting Hardy - Weinberg Equilibrium?
1- Source of new allelic/genetic variation:
– Mutation
2 - Mechanisms that alter existing genetic variation:
Migration (in and out)
– Positive or negative selection
– Genetic drift – chance fluctuations (smallpopulations)
– Non-random mating
Example of mechanism happens when there are large deviations are found?
exposure to environmental toxins
Example of Heterozygote Advantage?.
▪ Sickle-cell disease
Explain Genetic drift and population bottlenecks?
If populations are reduced to a small number of individuals - a population bottleneck, genetic drift can reduce the genetic variation
What inbreeding and outbreeding increases?.
Inbreeding leads to an increase in homozygosity
(assortative mating)
Out breeding leads to an increase in heterozygosity
