Bellringer: HAVE A SEAT!!! (In a desk – no one at lab benches) Get out your Pedigree handouts from yesterday and check your answers with a neighbor.

Do Now- Please complete on pg Do Now- Please complete on pg.56 of your BIN (under the practice from last class). Write questions and answers: 1. In mice, the dominant allele for eye color is black (B), and the recessive allele is red eyes (b). If two heterozygous parents are crossed, what will be all the possible genotypes and phenotypes of the offspring? Genotype of offspring: ____________Phenotype of offspring: ______________ 2. Yellow is dominant to green in seed color in pea plants. What are the phenotypes of the following genotypes? Homozygous recessive: Heterozygous: Homozygous dominant:

Alternative Patterns of Inheritance

Mendelian Genetics (Complete Dominance) Only two possible Phenotypes: either the dominant one or recessive one. Tall plant X Short plant = Tall plant (TT) (tt) (Tt)

Non-Mendelian Genetics But, not all inheritance is based on the rules of Complete Dominance!!

Nonmendelian Genetics Introduction Mendelian Genetics describes inheritance patterns based on Complete Dominance or Recessiveness. There are other types of inheritance that Mendel never considered: Incomplete Inheritance Codominance Multiple Alleles Polygenic Traits Sex-linked Nonmendelian Genetics

CoDominance Both traits are dominant, and show up in the phenotype together. Co means “together” Black Cow X White Cow = Spotted Cow (BB) (WW) (BW)

Possible phenotypes are a black cow, 2 spotted cows, and a white cow CoDominance Problem What are all the possible phenotypes when two spotted cows are bred? B W Possible phenotypes are a black cow, 2 spotted cows, and a white cow B BB BW W BW WW

What is an example of codominance? Cattle: A cross between a black bull and a white cow. The calves are spotted with black and white spots In other words, BOTH alleles are expressed A 1:2:1 phenotype ratio is characteristic of codominance

Incomplete dominance One allele is not dominant over another, as a result, there appears to be blending. Red Flower X White Flower = Pink (RR) (WW) (RW)

Incomplete Inheritance Problem What is the probability of pink flowers if pink flowers are bred with red flowers? R R 50% chance of Pink Flowers R RR RR W RW RW

Incomplete Dominance Practice Sponge Bob and his pal Patrick love to go jelly fishing at Jellyfish Fields! The fields are home to a special type of green jellyfish known as Goobers and only really great jelly fishermen are lucky enough to catch some on every trip. Many of the jellyfish are yellow (YY) or blue (BB), but some end up green as a result of incomplete dominance. Use this information to help you complete each question below. What would happen if Sponge Bob and Patrick crossed two “goobers” or green jellyfish? Complete the Punnett square to help you determine the probability for each color of jellyfish.

Checkpoint How are Incomplete and Codominace different? How are they the same?

What are Multiple Alleles? Some traits are controlled by genes for which more than two alleles exist. This is called multiple alleles. Remember that, even if more than two alleles exist in the population, each individual only possesses two…one inherited from each parent.

Multiple Alleles When more than 2 varieties exist in a trait. Many animals have a variety of coat colors.

What is an example of multiple alleles? Blood Type: A B AB O

Multiple Alleles Practice Problem You are blood type O and you marry a person with blood type AB. What are the possible blood types of your offspring?

Multiple Alleles Practice Problem

Polygenic Traits Require more than one gene (allele) to determine trait. Skin tone is determined by 4-6 genes—that means that there may be six different chromosomes involved!

Sex-linked Inheritance Genes for some traits are found on the sex chromosomes (X or Y) Most of these traits are recessive In females, the trait will be expressed only if both X chromosomes have the gene In males, the trait will be expressed if one X chromosome has the gene. Females who have one effected X chromosome are called Carriers

What is an example of a sex-linked trait? Color Deficiency: 8% of boys and .5% girls

Color blindness is a sex-linked recessive trait Color blindness is a sex-linked recessive trait. The gene for this trait is inherited through the X chromosome. If a heterozygous woman with normal vision has children with a man who is colorblind, what are the chances that their children will be colorblind? Will any children be carriers of the trait? Xc Y X XXc XY XXc XY