No Bell Work today! Set up the next page in your journal… Page: 44 Date: Title: Genetics – Incomplete Dominance Essential Question: How can I predict genetic outcomes of non-Mendelian traits?

Remember! What we’ve done so far is called MENDELIAN GENETICS. There is one dominant trait and one recessive trait – no in-between! Today we’ll look at something that follows a different rule…

Incomplete Dominance: when the genotype is heterozygous, the phenotype is a blend (ex. red + white = pink) Note: Sometimes, we write this by using an abbreviation of the trait in a capital letter (C =color) and the alleles as a superscript (C R = red flower) or subscript (C R ).

1. In a plant, long stems are dominant (S L ) to short stems (S S ). The heterozygous genotype will produce medium stems. If a long stemmed plant and a short stemmed plant are crossed, what are the expected phenotypes of their offspring? SLSL SLSL S S SLSSSLSS SLSSSLSS SLSSSLSS SLSSSLSS S L S L = Long S L S S = Medium S S S S = Short DAD = S L S L MOM = S S S S 100% medium stems

Spongebob loves growing flowers for his gal pal, Sandy. She loves the Poofkin flowers—red, purple, and blue! Interestingly enough, the Poofkin flowers display incomplete dominance in their genes for color. 1. Using “C R ” for red and “C B ” for blue, what would be the genotypes for the following phenotypes? red: ______ purple: _____blue: _____ 2. Complete a Punnett square to cross a red Poofkin and a purple Poofkin. What are the expected phenotypes of their offspring? CRCRCRCR CRCBCRCB CBCBCBCB CRCR CRCR CRCR CBCB CRCRCRCR CRCRCRCR CRCBCRCB CRCBCRCB 50% red 50% purple

Coat color in mice is incompletely dominant. Yellow and white-colored mice are homozygous, while cream-colored mice are heterozygous. If two cream-colored mice mate, what phenotypic ratio can we expect of their offspring? CYCY CWCW CYCY CWCW CYCYCYCY CYCWCYCW CYCWCYCW CWCWCWCW C Y C Y = yellow C Y C W = cream C W C W = white DAD = C Y C W MOM = C Y C W 1 yellow : 2 cream : 1 white

For the rest of today… Work on the Incomplete Dominance Practice Problems. Anything you don’t finish in class is HOMEWORK!!

No Bell Work today! Set up the next page in your journal… Page: 45 Date: Title: Genetics – Codominance Essential Question: How can I predict genetic outcomes of non-Mendelian traits?

Codominance: when the genotype is heterozygous, both phenotypes appear equally Codominance produces spots, stripes, etc. Note: when writing we show this with two different capital letters

1. A certain type of flower can be purple, white, or spotted. What would be the phenotypic outcome for two spotted flowers that were bred together? P W P W PP PW WW Purple = PP Spotted = PW White = WW DAD = PW MOM = PW 25% purple, 50% spotted, 25% white

Blood Type is trait that is both codominant and has multiple alleles (meaning more than two). * A and B are codominant, O is recessive. * Can also be written as I A I B for Type AB blood, ii for Type O, etc. Blood Type You can GIVE blood to… You can RECEIVE blood from… AA or ABA or O BB or ABB or O ABAB only!Anyone OAll typesO only!

3. What would be the expected phenotypes if a woman heterozygous for type A blood and a type AB man had children? AB A O AA AB AOBO Type A = AA, AO Type AB = AB Type B = BB, BO Type O = OO DAD = AB MOM = AO 50% Type A, 25% Type AB, 25% Type B

For the rest of today… Complete your Blood Typing worksheet. Anything you don’t finish in class today is HOMEWORK!

No Bell Work today! Set up the next page in your journal… Page: 46 Date: Title: Genetics – Sex-linked Essential Question: How can I predict genetic outcomes of non-Mendelian traits?

What do you think a “sex-linked” trait is? Examples?

Remember! Everyone inherits an X chromosome from mom and either an X (girls) or a Y (boys) from dad.

Sex-linked traits: determined by genes carried on either the X or Y chromosome If they are carried on the X-chromosome they are referred to as “X-linked” If they are carried on the Y chromosome they are referred to as “Y-linked” Y-linked disorders are very rare and often cause infertility in men

X-linked dominant Any affected chromosome will cause the trait to appear These conditions (such as vitamin D resistant rickets) are rare and can affect both men and women Men are more affected than women Both men and women can pass on the affected chromosome to their children

2. Rickets is an x-linked dominant trait. What would be the phenotypic outcome if a normal woman and a man with rickets had children? XRXR Y X X XRXXRX XY XRXXRX X R = rickets chromosome X = normal chromosome DAD = X R Y MOM = XX Their daughters would have rickets and their sons would not

In 18 words summarize these two diagrams.

X-linked recessive Women must have two affected chromosomes to show the trait; men with an affected X will show the trait These disorders (such as hemophilia and color blindness) more frequently affect men than women GenotypePhenotype XYMan who can see all colors XCYXCYColorblind man XXWoman who can see all colors XCXXCXWoman who can see all colors (carrier) XCXCXCXC Colorblind woman

3. Colorblindness is an X-linked recessive trait. What would be the expected outcome if a carrier woman (X C X) and a normal man had children? X Y XCXC X XCXXCX XCYXCY XX XY X C = colorblindness chromosome X = normal chromosome DAD = XY MOM = X C X DAUGHTERS: 50% carrier, 50% normal SONS: 50% colorblind, 50% normal

Pedigree: a diagram that shows relationships within a family; typically shows the occurrence of a particular trait

Your turn! You have the rest of the period to complete the “Flipnob Family Pedigree”! Read the provided information carefully. Anything you don’t finish in class today is HOMEWORK! Remember, your Human Pedigree – Family Tree assignment is due tomorrow as well!