LECTURE 9 - Quantitative Inheritance Flashcards
2 TYPES of GENETIC TRAITS
+ difference in terms of…
- discrete or continuous?
- described or measured by?
- effect of environment
- controlled by how many genes?
- Quantitative
- continuous
- described using measurable units
- largely affected by the environment
- controlled by multiple genes - Qualitative
- discrete (has this trait or not) / categorical
- classified on either-or bases
- less affected by environment
- controlled by 1-2 genes
what do you call a pattern of inheritance where a single gene controls a trait?
what type of genetic trait is this expressed?
what is its opposite?
Mendelian Inheritance
or
Monogenic Inheritance
in QUALITATIVE GENETIC TRAITS
in quantitative genetic traits, it s called POLYGENIC INHERITANCE
3 TYPES of Quantitative Traits - Polygenic Inheritance
- Meristic Trait
- discrete
- counted as not measurable
- controlled by many genes - Threshold Trait
- traits are either present or absent
- controlled by many genes - Continuous Trait
- traits are measured (may decimal)
- controlled by many genes
POLYGENIC INHERITANCE
- how many genes affect a single trait?
- each ____ will contribute _____ & ____ to the trait
- multiple genes
- allele
- additively and equally
*more dark skin alleles will result n a darker shade
PHENOTYPIC VARIANCE
- the variance observed across a ____ due to ___
- denoted by ____
- formula?
- population
- phenotype
- Vp
Vp = Vg + Ve + Vgxe
Vg - variance due to genotypic differences
Ve- variance due to environmental factors
Vgxe - variance due to interaction of genotype and environment
PHENOTYPIC VARIANCE
- can this be estimated?
It is DIFFICULT TO ESTIMATE but can be assumed to be equal to 0
GENOTYPIC VARIANCE
- formula?
Vg = Va + Vd + Vi
Va = variance due to additive gene effects
Vd = variance due to dominance gene effects
Vi = = variance due to epistatic gene effects
GENOTYPIC VARIANCE
- can this be measured?
It is DIFFICULT TO MEASURE but can be assumed to be equal to 0
UNLESS given in the problem
