Population Genomics Flashcards
define heritability
Degree to which genetic variation accounts for phenotypic variation seen in a population
what does snpedia show
heritability data for different phenotypes. used monovular twins for this data
what is a qualitative trait
similar meaning to phenotype
dichotomous - affected/not affected
categoric
whats is a quantitative trait
measurable phenotype, eg fruit size.
cumulative actions of multiple alleles.
continuous distribution of alleles.
example of a qualitative trait
PKU - phenylalanine hydroxylase - characterised by intellectual disability, microcephaly, seizures, eczema.
define genetic drift
change in allele frequency in a popualtion due to random sampling of organisms.
Time change of allele frequency
when allele frequency reaches 100% it is…
fixation
what is the founder effect?
loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. As a result of the loss of genetic variation, the new population may be distinctively different, both in genotype and phenotype.
what is a bottleneck
reduction in size of population due to environmental events or human activities
what is nucleotide diversity?
Degree of polymorphism within a population
average number of nucleotide differences per site between 2 DNA sequences
denoted by π
define a selective sweep
Selective Sweep : Reduction of diversity among the nucleotides in neighboring DNA of a mutation as the result of the recent fixation of a beneficial allele due to strong selection.
what is 23 and me?
A privately held personal genomics and biotechnology company based in Mountain View, California.
Genomic prediction. Sequence DNA and the make reports of predicted traits, disease risks, carrier status.
what is genomic selection
Select particular individuals to archive better phenotype (performance).
GWAS
genome wide association studies
GWAS
genome wide association studies
see association between phenotype and genotype do stat test on allele freq at each locus.
To see if any variants are associated with the trait.
define gene pool
collection of all genes in all individuals in a population
how do you calculate allele frequency in a gene pool?
percentage of each allele
what does population genomica concern?
changes in allele frequencies
define gene
molecular unit of heredity
encodes functional protein
define gene
define allele
molecular unit of heredity
encodes functional protein
one of a number alternative forms of the same locus
point mutation
one NT replaced by another
what are inversion and translocation mutations?
inversion - reverses direction of part of chromosome
translocation - part of one chr attaches to another
domestication
process by which plants or animals are genetically modified over time by humans to more desirable traits
what is gene introgression
..
gives gene flow from one population to another. eg by mating 2 species