Lecture 31- Mendelian genetics

Polygenetic inheritance

Occurs when many genes contribute to a single phenotype ex/ height, human skin colour

Phenotype is quantitative compared to the either or discrete traits

Can polygenic traits be affected by environment?

Yes many are

Pedigree analysis

Traces a character through family generations

If a trait is dominant, it will

Appear more often in the progeny

An offspring displaying that trait will always have a parent with the trait

If a trait is recessive it will

Appear less often in the progeny

An offspring displaying that trait can have parents that do not display that display

A recessive allele usually results in a

Protein malfunction or lack of protein altogether

Carriers

Heterozygotes that usually have the dominant phenotype since they have one copy of the dominant allele. They can pass on the recessive allele to their offspring

What results in the recessive phenotype

Only homozygous recessive genotypes

If Polygenic traits are when many genes contribute to one phenotype, what is it called when one gene contributes to many phenotypes

Pleiotropy

Are dominant lethal alleles or recessive lethal alleles more rare?

Dominant lethal alleles