Journal 7 When setting up a punnett square there are _______ (#) of alleles for each person. Monohybrid crosses are _______ (#) of traits. Complete the cross for: Homozygous Dominant x Homozygous Recessive. What are the genotypes and phenotypes?

Heredity not following the Rules

Incomplete dominance A heterozygous condition in which both alleles are partially expressed, often producing an intermediate or blended phenotype (which is different than either of the homozygous forms). Snapdragons

Incomplete dominance Snapdragons

Incomplete dominance RR R’R’ I n I n c o m p l e t e D O M I N A N C E, u s e t h e S A M E l e t t e r s s i n c e t h e y b o t h a r e w e a k ! RR’ RRRR’ R’R’

Incomplete dominance Palomino horses are a cross between a chestnut horse and a cremello (white) color horse. Practice the cross using a Punnet Square. HH’ H H H’

Codominance Codominance –Neither phenotype is dominant. Instead, the individual expresses both phenotypes. both Co – both are dominant enough to be expressed!! Dominique chickens

Codominance BB - Black WW - White BW - Black and White BWBWBWBW BWBWBWBW B B WW Cross a black chicken with a white chicken and what to you get if the traits are CODOMINANT? Predict the outcome if BOTH chickens are dominique (black and white) ???? I n C O D O M I N A N C E, u s e D I F F E R E N T l e t t e r s s i n c e t h e y b o t h a r e s t r o n g !

Codominance BB - Black WW - White BW - Black and WhiteBBWBW BWBWW B W BW BB=1 BW=2 WW=1

Codominance Another example of codominance is ABO blood typing. The blood types A and B are codominant to each other; however, type O is actually recessive to A and B.

Codominance BB or BO AA or AO AB OO When both alleles exist, both are present!

Codominance Blood Group Antibodies Can give blood to… Can receive blood from ABNoneAB A, B, AB, and O ABA and ABA and O BAB and ABB and O OA and B A, B, AB, and O O Which group is the universal donor? Which group is the universal recipient?

Practicing Blood Types A man of blood type AA marries a woman with blood type AB. What is the chance they will have a child with type AB blood?AABABAABAB A A AB AB?

Practicing Blood Types #2 A man of blood type B marries a woman with blood type O. What is the chance they will have a child with type O blood? BOBOBOBO BOBOBOBO B B OO O? BOBOBOBOOO B O OO T h e r e c o u l d b e 2 g e n o t y p e s f o r t h e m a n : B B o r B O

Codominance Blood Group AntigensAntibodies Can give blood to… Can receive blood from ABA and BNoneAB A, B, AB, and O AABA and ABA and O BBAB and ABB and O ONoneA and B A, B, AB, and O O

Multiple Alleles An individual can only have 2 genes thus 2 alleles for a trait, but there could be more than 2 alleles present in a population. This type of inheritance is known as multiple alleles. Why can you only have 2 genes for each trait? Because… you only have 2 of each type of chromosome!!

Multiple Alleles - examples In Blood typing, there are 2 possible alleles (genes) that could could inherit – A, B, and O, but you can only inherit 2 of them. In this case, blood typing is also a trait that has multiple alleles. Coat color in rabbits is inherited as a series of multiple alleles.

How many alleles are there for rabbit coat color?

Multiple Alleles - examples What are all of the possible genotypes for a 1.dark-gray coated rabbit? (4) CC Cc ch Cc h Cc 2.chinchilla rabbit (3) c ch c ch c ch c h c ch c 3.Himilayan rabbit(2) c h c h c h c 4.White rabbit (1) cc Why is dark gray a capital C?

Multiple Alleles - examples Predict the phenotype for a rabbit with a c ch c h. Chinchilla Is it possible to obtain a white rabbit if one parent is white and the other is chinchilla? Yes. Only if the chichilla is c ch c

Sex-Link Traits Genetic linkage has to do with the X and Y sex chromosomes. Genes that are carried by either sex chromosome are said to be sex linked. Examples of Sex-linked Traits: Red-green colorblindness Male Pattern Baldness Hemophilia Duchenne Muscular Dystrophy

Example Problem Set 1: Colorblind Father & Normal Mother Problem Set 2: Colorblind Father & Carrier Mother

POPQUIZ!! (Just kidding) A roan cow is the product of a red cow and a white cow. What type of inheritance is exhibited? A. Complete dominance B. Codominance C. Incomplete dominance D. Sex-linked E. Multiple alleles

POPQUIZ!! Curly headed people have the genotype HH, while straight headed people have the genotype hh. A wavy headed person is heterozygous. What type of inheritance does this exhibit? A. Complete dominance B. Codominance C. Incomplete dominance D. Sex-linked E. Multiple alleles

POPQUIZ!! Hair loss is a trait caused by a gene located on the X chromosome. This trait would be considered - A. Complete dominance B. Codominance C. Incomplete dominance D. Sex-linked E. Multiple alleles

POPQUIZ!! Kim’s has always wondered why her 2 nd toe is longer than her first. She recently discovered that it is a dominant trait. This trait is considered to exhibit - A. Complete dominance B. Codominance C. Incomplete dominance D. Sex-linked E. Multiple alleles

POPQUIZ!! Here is an easy one! Blood types fall under the category of which type of inheritance? A. Complete dominance B. Codominance C. Incomplete dominance D. Sex-linked E. Multiple alleles H E E H E E

Closing Write a brief description of each: Codominance Incomplete Dominance Sex Linked Multiple Alleles

Journal 8 Complete the cross for Incomplete Dominance: BB x WW. Include phenotypic ratio. Complete the following cross: A homozygous A blood man and a Heterzygous B blood female. Include phenotypic ratio.

Dihybrid Crosses

Working with two gene pairs (Produces a Dihybred Cross) – example: Eye Color and Hair Color These Characters were located on different Chromosomes Gene for ONE trait does NOT influence the movement of the gene for the other trait This Independent movement called the Law of Independent Assortment

Example: G = dominant gene for Yellow g = Recessive gene for Green W = dominant gene for Round w = Recessive gene for Wrinkled

F1 = GgWw x GgWw F2 = Genotypes (Punnett Square) GWGwgWgw GW GGWW Round GGWw Round GgWW Round GgWw Round Gw GGWw Round GGww Wrinkled GgWw Round Ggww Wrinkled gW GgWW Round GgWw Round ggWW Round ggWw Round gw GgWw Round Ggww Wrinkled ggWw Round ggww Wrinkled

Closing What is the purpose of a dihybrid cross? Do you prefer the long 16 box format or the 2 small boxes of 4?