Signatures of Selection Flashcards
What are the 7 forms of selection?
Positive, negative, balancing, frequency dependent, background, runaway and heterosis (hybrid vigour).
What is Tajima’s D?
The difference between 2 measures of genetic diversity - mean number of pairwise differences and number of segregating sites.
What does a Tajima’s D value indicate?
D = 0 means equilibrium.
D < 0 means positive selection.
D > 0 means balancing selection.
What are the 3 types of quantitative traits?
Continuous, meristic and discrete.
What is a continuous trait?
A trait where there is an infinite number of values possible. For practical reasons they are often grouped into classes.
What is a meristic trait?
A trait that is expressed in discrete integral classes.
What is a discrete trait?
A trait that is either displayed or not.
What is quantitative trait locus (QTL) mapping?
A method utilised to define the general chromosomal position of the gene or genetic variants that influences the magnitude of measurable traits.
What is the main assumption in quantitative trait locus mapping?
There is no genotype-phenotype interaction.
