• Incomplete Dominance

– One allele is not completely dominant over the other.

– Offspring shows blending phenotype

– Eg: White flower

crosses with a red = pink flower.

Beyond Dominant and Recessive• Codominance

– Both alleles contribute to the phenotype.

– Eg: Red cow X White Cow = Roan Cow.

– Eg: blood type

phenotype A B AB O

IA IA

or

IA i

IB IB

or

IB iIA IB i i

phenotype

genotype

Beyond Dominant and Recessive• Multiple Alleles

– One gene have more than two alleles

– Eg: Rabbit coat color, four alleles: • C > cch > ch> c

– Eg: blood type, three alleles• IA = IB > i

Full

• Polygenic traits

– Several genes control the trait.

– Wide range phenotypes. – Eg: Skin color, height

Beyond Dominant and Recessive

• Sex linkage (x-linked)

– Some genes are present on the X chromosome but missing on the shorter Y chromosome.

Beyond Dominant and Recessive

1) Color blindness

– more common in males than in females.

Beyond Dominant and Recessive

2) Haemophilia

– unable to clot blood