Genetics Fill-In Notes Part 2 Mrs. Kooiman

Incomplete Dominance When a cross between organisms with two different phenotypes produces offspring with a third phenotype that is a blend of the parental traits. When a cross between organisms with two different phenotypes produces offspring with a third phenotype that is a blend of the parental traits.

Incomplete Dominance Red and White flowered plants that produce pink offspring. Example: Red and White flowered plants that produce pink offspring. In this case, you can use two different letters in the Punnett Square. In this case, you can use two different letters in the Punnett Square. Red Flowered Plant (RR) X White Flowered Plant (WW) The heterozygous offspring are The heterozygous offspring are Pink (RW)

Incomplete Dominance R WWWW RW

Co-Dominance A cross between organisms with two different phenotypes produces offspring with a third phenotype in which both of the parental traits appear together. A cross between organisms with two different phenotypes produces offspring with a third phenotype in which both of the parental traits appear together.

Co-Dominance Example: Black and white haired horses produce offspring with a mix of black a white fur (or spots) Example: Black and white haired horses produce offspring with a mix of black a white fur (or spots) Black haired horse (BB) X White haired horse (WW) The heterozygous offspring are The heterozygous offspring are black and white (BW)

Co-Dominance B WWWW BW

Pedigree Diagram A diagram of family history that shows how a trait is inherited over several generations. Similar to a family tree that can help to determine if children will inherit a disorder.

Pedigree Diagram

Sex-Linked Traits A trait whose allele is located on the x- chromosome. Most are recessive. A trait whose allele is located on the x- chromosome. Most are recessive. Since males only have one X-chromosome (XY) a male who carries a recessive allele will have the disorder. Since males only have one X-chromosome (XY) a male who carries a recessive allele will have the disorder. Females have two X-chromosomes (XX) and will ONLY show the disorder if they inherit both recessive alleles. Just like how you normally do not see a recessive trait unless the genotype is homozygous recessive. Otherwise, the normal/dominant allele will mask the recessive allele. Females have two X-chromosomes (XX) and will ONLY show the disorder if they inherit both recessive alleles. Just like how you normally do not see a recessive trait unless the genotype is homozygous recessive. Otherwise, the normal/dominant allele will mask the recessive allele.