Cross a homozygous dominant green plant with a heterozygous green plant. What are the genotypic and phenotypic ratios. Agenda for Tuesday Jan 3rd Test stuff Lab

Cross 2 heterozygous green pea seed plants Cross 2 heterozygous green pea seed plants. What is the chance to have a yellow (recessive trait) pea seed? Agenda for Wednesday Jan 4th 1. Complex patterns of inheritance Incomplete and Co-dominance Quiz Monday

Complete Dominance a heterozygous individual’s phenotype will show dominant trait

Purebred red snapdragons were crossed with purebred white snapdragons all offspring were pink

Incomplete Dominance one allele for a trait is not completely dominant over the other allele Combined phenotype (blended) R = allele for red flowers W = allele for white flowers red x white ---> pink RR x WW ---> 100% RW

Co-dominance In COdominance, the "recessive" & "dominant" traits appear together in the phenotype of hybrid (heterozygous) organisms

Practice Set up genotypes for the phenotypes listed in each set. Remember that the "medium" trait is always heterozygous. a) Birds can be blue, white, or white with blue-tipped feathers. b) Flowers can be white, pink, or red. c) A Hoo can have curly hair, spiked hair, or a mix of both curly and spiked. D) A person can be tall, medium, or short.

1. Write the genotypes for the pictured phenotypes 2 1. Write the genotypes for the pictured phenotypes 2. Show the cross between a star-eyed and a circle eyed. What are the phenotypes of the offspring? What are the genotypes?

3. Show the cross between a circle-star eyed, and a circle eyed 3. Show the cross between a circle-star eyed, and a circle eyed. How many of the offspring are circle-eyed? How many of the offspring are circle-star eyed? Write the genotypic and phenotypic ratios. 4. Show the cross between two circle-star eyed. How many of the offspring are circle-eyed? How many of the offspring are circle-star eyed? How many are star eyed?

In humans, straight hair (SS) and curly hair (CC) are co-dominant traits that result in hybrids that have wavy hair (SC). Cross a Straight hair female with a wavy haired male. What are the chances of having a curly haired child? What are the chances of having a straight hair child? What are the chances of having a wavy hair child? Agenda for Thursday Jan 5th 1. Sex Linked traits Quiz Monday – incomplete/codominance/sex linked traits/multiple alleles

Sex Determination Thomas Hunt Morgan – studied fruit flies in the early 1900’s

Sex Determination Observed that one pair of chromosomes was different between males and females Large one named “X” chromosome Smaller one named “Y” chromosome XX = female; XY = male

XY XX X Y X X X X XX Female XX Female X XY Male XY Male Y 50% Female; 50% Male

Sex Linkage Sex Linkage: the presence of a gene on a sex chromosome (X or Y) X-linked genes: genes found on the X chromosome X chromosome carries more genes Y-linked genes: genes found on the Y chromosome

Fruit Fly Eye Color Fruit flies normally have red eyes Red is dominant; white is recessive A few males have white eyes

Morgan’s Fruit Fly Experiments Red-eyed female (XRXR) x White-eyed male (XrY) XR XR XRXr XRXr RESULTS: F1 generation – all red-eyed Xr XRY XRY Y

Morgan’s Fruit Fly Experiments Red-eyed female (XRXr) x Red-eyed male (XRY) XR Xr RESULTS: F2 generation – 3 red-eyed and 1 white-eyed ** all white-eyed where males…why? XRXR XRXr XR XRY XrY Y

Morgan’s Conclusions Gene for eye color is carried on the X chromosome = eye color is an X-linked trait Y chromosome does not carry a gene for eye color Red-eyed = XRXR, XRXr , XRY White-eyed = XrXr, XrY

In humans colorblindness (b) is an example of a sex-linked recessive trait. A male without colorblindness marries a female who isn’t colorblind but carries the allele. What are the phenotypes of the offspring? What are the genotypes of the offspring? What are the genotypic ratios? What are the phenotypic ratios? What is the percent chance of each genotype? What is the percent chance of each phenotype?

In fruit flies red eye color (R) is dominant to white eyes (r) and is a sex linked trait. A heterozygous red eye female mates with a red eye male. What are the phenotypes of the offspring? What are the genotypes of the offspring? What are the genotypic ratios? What are the phenotypic ratios? What is the percent chance of each genotype? What is the percent chance of each phenotype?

In fruit flies red eye color (R) is dominant to white eyes (r) In fruit flies red eye color (R) is dominant to white eyes (r). Cross a heterozygous female with a white eye male. What are the phenotypic and genotypic ratios? Agenda for Friday Jan 6th 1. Practice with sex linked traits 2. Multiple alleles Quiz Tuesday

In fruit flies red eye color (R) is dominant to white eyes (r) and is a sex linked trait. A heterozygous red eye female mates with a white eye male. How many males will have white eyes?

In humans colorblindness (b) is an example of a sex-linked recessive trait. A male with colorblindness marries a female who isn’t colorblind and does not carry the allele. What is the chance they will have a child that is colorblind?

Multiple Alleles Multiple alleles – traits determined by more than 2 alleles Increases possible number of genotypes & phenotypes We have 2 alleles (1 from mom, 1 from dad) Blood groups (ABO), O is recessive (i allele) ALLELE IA IB i CODES FOR Type "A" Blood Type "B" Blood Type "O" Blood

GENOTYPES IAIA IAi RESULTING PHENOTYPES Type A Type A IBIB IBi Type B Type B IAIB Type AB ii Type O

More alleles means more combinations there are 6 different genotypes & 4 different phenotypes for blood type 2 genotypes for both "A" & "B" blood --- either homozygous (IAIA or IBIB) or heterozygous with one recessive allele for "O" (IAi or IBi). The only genotype for "O" blood is homozygous recessive (ii). And lastly, what's the deal with "AB" blood?  What is this an example of?  The "A" trait & the "B" trait appear together in the phenotype.

Problems A woman with Type O blood and a man who is Type AB have are expecting a child.  What are the possible blood types of the kid? What are the possible blood types of a child who's parents are both heterozygous for "B" blood type?

One More What are the chances of a woman with Type AB and a man with Type A having a child with Type O?

What are the chances of a woman with Type AB and a man with Type O having a child with Type O? Agenda for Monday Jan 9th Review Video Quiz Tomorrow

What are the chances of a woman with Type AB and a man with Type AB having a child with Type A? Agenda for Tuesday Jan 10th Quiz Breeding styrofoam monsters Lab Quiz/test Friday

Epistasis Epistasis – one allele hides/suppresses another allele

Polygenic Phenotype depends on alleles in multiple genes Skin color, height, eye color Continuous progression in expression of traits