NONMENDELIAN GENETICSTest Monday 1/31

Vocab Check…

Chromosome: DNA that has been tightly wound together, individuals genetic code

Gene: segment on a chromosome that code for a trait

Allele: distinct form of a gene

Multiple Alleles

When three or more alleles are formed in a population. These genes have multiple alleles

EX: Blood Type– A, AB, B, O

Blood Types

O is recessive

A and B are both dominant (codominant)

Blood Types

How common are the blood types?

Transfusions:

O+ A+ B+ AB+ O- A- B- AB-

37.4% 35.7% 8.5% 3.4% 6.6% 6.3% 1.5% 0.6%

Phenotype(Blood Type Genotype

Antigen on Red Blood Cell

Safe Transfusions

To From

Blood Types Cross a female who is heterozygous

with A blood and a male who is heterozygous with B blood

Codominance

When both alleles are expressed (seen) fully

Happens in the heterozygous (Bb, Hh)

EX: speckled chickens and Blood Type

Codominance in Chickens

In chickens:BB=blackBb=speckled (codominant)bb=white

Work a punnett square crossing a black rooster with a white hen

Codominance in Chickens

What are the genotypes from the cross?

What are the phenotypes from the cross?

Phenotype is not read as a dominant look! In codominant traits both alleles are expressed hence the speckled look

Codominance in Chickens

X

Codominance in Palomino Horses

X

Incomplete Dominance

When two different alleles for the same trait COMBINE, but neither “wins” expression over the other

Shows a BLENDED look phenotype in the heterozygous (Bb, Hh)

Incomplete Dominance—Snapdragons

Snapdragons inherit color by incomplete dominance

RR=redrr=whiteRr= PINK

(blended look)

Cross 2 heterozygous snapdragons

Incomplete dominance--Snapdragons

What are the genotypes from the cross?

What are the phenotypes from the cross?

Phenotype is not read as a dominant look! In incomplete dominant traits the allele is expressed as BLENDED

Incomplete Dominance--Snapdragons

X

Incomplete Dominance—Rabbits

Alleles are BLENDED—black rabbit crossed with a white rabbit makes a gray rabbit

X

Sex-Linked Traits

Traits which are carried on the X chromosome

More common in MALES EX: colorblindness, hemophelias

Sex-Linked Traits--Colorblindness

Colorblindness is a recessive trait

Phenotype GenotypeFemale normal XCXC

Female carrier XCXc

Female colorblind

XcXc

Male normal XCYMale colorblind XcY

Sex-Linked Traits--Colorblindness

Cross a female carrier with a normal male

What are the genotypes and phenotypes?