Bellringer 10/29 In rabbits, white fur color (W) is dominant to black, and long ears (L) are dominant to short. Draw a Punnett square that represents the cross between two rabbits heterozygous for both traits. What are the phenotype and genotype ratios? In humans, polydactylism (having an extra finger on each hand) is dominant to the typical 5-finger arrangement. Tongue rolling is dominant to not being able to roll one’s tongue. A man who is homozygous for 5-fingers and who cannot roll their tongue has children with a woman who is heterozygous for polydactylism and tongue rolling. Draw a Punnett square that represents the cross. What is the probability the couple will produce a polydactyl baby who cannot roll their tongue?

In rabbits, white fur color (W) is dominant to black, and long ears (L) are dominant to short. Draw a Punnett square that represents the cross between two rabbits heterozygous for both traits. What are the phenotype and genotype ratios?

In humans, polydactylism (having an extra finger on each hand) is dominant to the typical 5-finger arrangement. Tongue rolling is dominant to not being able to roll one’s tongue. A man who is homozygous for 5-fingers and who cannot roll their tongue has children with a woman who is heterozygous for polydactylism and tongue rolling. Draw a Punnett square that represents the cross. What is the probability the couple will produce a polydactyl baby who cannot roll their tongue?

Beyond Mendel

Mendelian Inheritance (aka complete dominance) When one trait is clearly dominant over another. Mendel was very fortunate that all the pea plant traits that he studied exhibited complete dominance.

Incomplete Dominance When neither allele is dominant over the other The heterozygote’s phenotype is a BLEND of the two homozygous phenotypes.

P generation  red x white RR x WW Genotypes: Phenotypes:

F1 generation  pink x pink Genotypes: Phenotypes: Genotypic ratio: Phenotypic ratio:

Codominance When neither allele is dominant over the other BOTH alleles show up in the heterozygote

P generation  black x white BB x WW Genotypes: Phenotypes:

Blood types are also codominant. Antigen B Antigen A Antigen A & B

AB blood type x AB blood type ___________ x __________ Genotypes: Phenotypes: Genotypic ratio: Phenotypic ratio:

Incomplete Dominance or Codominance? Birds can be blue, white, or white with blue-tipped feathers. Flowers can be white, pink, or red. A sneech can be tall, medium, or short. A bleexco can be spotted, black, or white. A Hoo can have curly hair, spiked hair, or a mix of curly and spiked hair.

Multiple Alleles  when three or more alleles code for one trait ex: blood type has three alleles (O is recessive) Genotype Phenotype IAIA (AA) A IAi (AO) IBIB (BB) B IBi (BO) IAIB (AB) AB ii (OO) O

Homozygous male type B x heterozygous female type A ___________ x ___________ Genotypes: Phenotypes: Genotypic ratio: Phenotypic ratio:

Male type O x female type AB ___________ x ___________ Genotypes: Phenotypes: Genotypic ratio: Phenotypic ratio:

If a boy has a blood type O and his sister has blood type AB, what are the genotypes and phenotypes of their parents?

Sex-linked Traits / X-linked Traits Located on the X chromosome (NOT Y!) Examples: hemophilia, color blindness

XHY x XHXh Trait: Hemophilia H = no hemophilia h = hemophilia (normal male) x (female carrier) XHY x XHXh HH = no hemophilia Hh = no hemophilia Hh = hemophilia XY = male XX = female

Most sex-linked, recessive traits – including hemophilia and color blindness – appear in males. This phenomenon is best explained by which statement? Males have an X chromosome with dominant genes. Most of the genes on the X and Y chromosomes of males are recessive. In males, the recessive sex-linked genes appear only on the Y chromosome. In males, the Y chromosome lacks the genes needed to mask the recessive genes on the X chromosome.

A couple has five children, all with blood type A A couple has five children, all with blood type A. The mother’s blood type is O, and the father’s blood type is A. Based on this information, which describes the most probable genotype of the father? Diploid Haploid Heterozygous Homozygous

Some flowers show incomplete dominance Some flowers show incomplete dominance. If RR = white and R’R’ = red, which phenotypic ratio would be expected in the offspring of two pink flowers? 1 red : 2 pink : 1 white 0 red : 4 pink : 0 white 3 red : 0 pink : 1 white 4 red : 0 pink : 0 white

Are you Finished? Worksheet Complete? Correct? Vocabulary? Missing work? Quiz on Wednesday (11.4) All content fair game Test moved to the 6th See me! =)