QTL Mapping

Question 1

QTL

Answer 1

Quantitative Trait Locus. Usually underlie continuous traits such as height. Must be polygenic (Controlled by 2 or more genes)
Must be polymorphic (2 or more forms of the allele) and must be linked to a polymorphic marker allele to be detected.

Question 2

Broad Sense Heritability

Answer 2

Ratio of total genetic variance to total phenotypic variance
H² = Vg/Vp Vp = Vg+Ve Vg = Va + Vd

Lower H² means more affected by environment.

Vp= Phenotypic Variation
Vg= Genetic variation
Ve= Environmental Variation
Va= Additive Genetic Variation (AA = 4, Aa = 3, aa = 2 , i.e. effects of many genes)
Vd= Dominance Genetic Variation (Dom. vs Rec.)

Question 3

Narrow Sense Heritability

Answer 3

Ratio of additive genetic variance to the total phenotypic variance.
h² = Va/Vp Vp = Vg+Ve Vg = Va + Vd

Lower h² means more affected by environment.

Vp= Phenotypic Variation
Vg= Genetic variation
Ve= Environmental Variation
Va= Additive Genetic Variation (AA = 4, Aa = 3, aa = 2 , i.e. effects of many genes)
Vd= Dominance Genetic Variation (Dom. vs Rec.)

Question 4

Logarithm of the odds ratio (LOD Score)

Answer 4

A significance test
Odds Ratio = Probability of the data occurring with a
QTL/Probability of the data occurring without a
QTL