patterns of inheritance review
TRANSCRIPT
Patterns of Inheritance Review
Degrees of Dominance
Complete Dominance - AA and Aa same phenotype
Incomplete Dominance - Aa has in-between/blended phenotype Codominance - Aa has both A and a
phenotype
Simple (Complete) Dominance
• LL or L l - short hair • l l - long hair
Co-dominanceBoth gene versions (alleles) are shownExample:
BB – black hairOO- orange hairBO – both black and orange hair
Incomplete Dominance
• Piebald spotting• ss - No white fur • SS- More than 50% white fur • Ss - Less than 50% white fur
The dominant allele cannot completely mask the recessive allele
What kind of dominance?
What kind of dominance?
What kind of dominance?
What kind of dominance?
What kind of dominance?
What kind of dominance?
What kind of dominance?
What kind of dominance?
What kind of dominance?
X-linked traits• genes found on the
X chromosome.• Females XX• Males XY• Orange and black
are codominant and on the X chromosome
Y-linked traits• Y-linked traits called
holandric inheritance.• Y-chromosome is small and
does not contain many genes
• Deletions on y chromosome male infertility
• SRY gene sex determining region
X-linked or holandric?
X-linked or holandric?
Multiple Alleles
More than 2 versions (alleles) for a single trait
Can have any dominance pattern
Multiple Alleles
• BB, Bb, Bbl – black hair• bb, bbl – brown hair• bl bl – cinnamon hair
Epistasis – when one gene controls the expression of another gene
• Most cats have the tabby gene
• Non-Agouti trait masks the tabby trait
Epistasis(standing upon)
• Dilute gene• DD and Dd – not dilute• dd – dilute – black become gray and orange
becomes cream
Epistasis or multiple alleles?
Epistasis or multiple alleles?
Epistasis or multiple alleles?
Pleiotropy A single gene can have
multiple effects on phenotype
ex multiple symptoms of sickle cell anemia (pain, jaundice, infections, fatigue, etc)
Pleiotropy in cats
• Dominant white gene can also cause blue eye color and deafness
Polygenic Inheritance
2 or more genes affect a single phenotypic trait Ex: Eye color, skin color, height
some traits also influenced by the environment - multifactorial inheritance
Pleiotropy, multifactorial, or polygenic?
Pleiotropy, multifactorial, or polygenic?
Pleiotropy, multifactorial, or polygenic?
Pleiotropy, multifactorial, or polygenic?
Pleiotropy, multifactorial, or polygenic?