Complex Patterns of Inheritance A Day: 5/13/16 B Day: 5/16/16 3 Weeks Until Finals Only 3 more lessons with new material!

Review If a person is heterozygous for a trait, do they show the dominant or recessive phenotype? Dominant

Complex Patterns What kind of traits can you think of that seem to be “blends” of other traits? Wavy hair looks like strait hair and curly hair blended Pink flowers look like a blend of white and red flowers

Incomplete Dominance Many traits result from alleles with a RANGE of dominance In many cases both the dominant and recessive alleles will make proteins – the dominant protein is just more visible

Incomplete Dominance In incomplete dominance, the heterozygous phenotype is a BLEND between the two homozygous phenotypes When an allele is neither dominant nor recessive: Uppercase letters with either subscripts or superscripts are used to represent different alleles

Codominance Sometimes both alleles are expressed completely and there is no blending Both traits are FULLY present Ex: Spots on a horse

Polygenic Most traits are the result of MULTIPLE genes interacting Skin color = 4 or more genes Eye color = 3 or more genes

Eye Color: Polygenic Trait

Codominant or Incomplete Dominance?

Co or incomplete? Co or incomplete?

Incomplete Dominance or Codominance? COWDOMINANCE

Blood Types Blood type is a codominant trait: 1. Type A: Blood has antigen A 2. Type B: Blood has antigen B 3. Type AB: Blood has antigen A & B 4. Type O: Blood has no antigens Which type best shows codominance? Rh Factor: Either you have Rh or you don’t A positive versus A negative

Blood Types

Videos! Blood Type Vid #1: https://www.youtube.com/watch? v=ttjn1jVACk8 Blood Type Vid #2: https://www.youtube.com/watch? v=xfZhb6lmxjk

Blood Types – Self Quiz In your own words, what makes the trait of blood types a codominant trait? Both A and B antigens can be present on blood cells at the same time The two traits do not blend together The two traits are both present How do you write a GENOTYPE for blood types? Use superscripts to show different alleles Give two examples of blood type genotypes IAIA or IAIB

Answer #1 Check yo self! Answer #2

Answers #3 & 4 YY

Answer #5

Hints for #9 The first step is to write out the GENOTYPE for the parents Fred Fish’s Genotype: Yyrr Olivia Fish’s Genotype: You figure this out on your own Next create all gamete possibilities for EACH of the parents Fred Fish’s gametes: Yr, Yr, yr, & yr Do Olivia’s gametes on your own Then create a Punnett Square for this problem: You need to use more than one allele per gamete Don’t just create a Punnett Square, answer the actual question 