loadingExceptions To Mendel’s Laws ( also called Non- Mendel’s Inheritance)
Additional Genetic Patterns
Mendel’s peas Complete Dominance
Other Patterns
Incomplete Dominance Codominance Lethal Alleles
Hierarchy of Dominance Multiple Alleles
(1) One gene affects many traits (Pleiotropy, 多效性)
(2) Two (or more) genes affect one trait (Gene Interactions and Polygenic Traits) (下册)
Two alleles per gene
One gene affects one trait
Additional Genetic Patterns
Mendel’s peas
Could not observe gender-specific traits
Equal contributions from both parents
Other Patterns
Sex-influenced traits (从性遗传) Sex-limited traits (限性遗传) Cytoplasmic Inheritance (下册) Genetic Maternal Effect (下册) Genomic Imprinting (基因组印记)
Trait expressed at same level Anticipation (早现) and stage of life
No environmental influence Environmental Effects
(一) Incomplete Dominance
Incomplete dominance: neither allele masks the other and both are observed as a blending in the heterozygote.
RR x R’R’ Red White RR’ pink
Four o’clock flowers R = red, R’ = white
Incomplete Dominance