Complete Dominance Complete dominance the allele that is

Complete Dominance • Complete dominance: the allele that is regarded as dominant completely masks the effect of the allele that is recessive. • Dominant alleles are written with capital letters and recessive alleles are written with lower case letters. For example, purple flowers are dominant to white flowers. A homozygous white flower is crossbred with a homozygous purple flower. What are the phenotypes of the offspring?

Incomplete Dominance: Both alleles are capitals because the alleles are not dominant or recessive **neither one takes over or hides …. not dominant or recessive…they MIX TOGETHER! Like mixing paint! The outcome is in-between!! R=Red Flowers B=Blue Flowers RR=Red Flowers BB=Blue Flowers RB=Purple Flowers Here’s one where red and white make pink

Try These Punnett Squares…please • Cross a Blue flower with a red flower. • Cross a red flower with a purple flower. • Cross two purple flowers.

Codominance • Same deal with the alleles…all letters will be capital. • This time they are both being dominant. • It’s like splattering one color on another-they both show up equally dominant. • For example, you have a homozygous black feathered chicken who mates with a homozygous white feathered chicken. Their offspring will have BOTH white and black feathers. • Results in a third phenotype: speckled.

So…Codominant Alleles R=Red Fish RR=Red Fish B= Blue Fish BB=Blue Fish RB=Red and Blue Fish (like spots or stripes)

Now Try These Punnett Squares…please • Cross a Blue fish with a red fish. • Cross a red fish with a red and blue fish. • Cross two red and blue fish.

Blood Type is also Codominant • Blood types A and B are codominant. • When present, they are both expressed. • However, Blood type O is recessive. • When present with dominant alleles, it is masked.

Blood Type Examples • A man with AB blood is married to a woman with AB blood. What blood types will their children be and in what proportion? • A woman with type A blood (genotype: AO) is married to a type B person (genotype: BO). What blood types will their children have?

Can You Pick Out the Co-dominant and Incompletely dominant Example? Silly Question…of course you can

See…You Did it

Sex-linked • Sex-linked traits are carried on the sex chromosomes. • The sex chromosomes are 23 pair. XX = female XY = male Because, males only have one X chromosome, they have a much greater chance of having sex-linked traits.

Examples of Sex-Linked Traits Hemophilia Colorblindness • a problem with the color • Blood lacks clotting factor, most of which -sensing cones in the are produced in the retina of the eye. liver. • You can’t see certain colors • Red/Green-most common • Blue Yellow • Achromatopsia-see greys only

Colorblindness Example • Colorblindness is a recessive disorder carried on the X-chromosome. • A female carrier of colorblindness and a normal male want to have children. What is the probability they will have a child who is colorblind?