Start-up for12/11/13 1. Summarize Mendel’s Law of Segregation. 2. Complete the following single trait crosses and answer the questions: Trait: Plant Height T = Tall t = short A. If you cross a heterozygous male (Tt) with a homozygous recessive female (tt), what percentage of the offspring do you expect will be short? (show your punnett square work) B. If you cross a homozygous dominant male with a homozygous recessive female, how many of the offspring will be short?

Start-up for 12/11/13 2. Complete the following single trait crosses and answer the questions: Trait: Plant Height T = Tall t = short A. If you cross a heterozygous male (Tt) with a homozygous recessive female (tt), what percentage of the offspring do you expect will be short? (show your punnett square work)

Start-up for 12/11/13 2. Complete the following single trait crosses and answer the questions: Trait: Plant Height T = Tall t = short B. If you cross a homozygous dominant male with a homozygous recessive female, how many of the offspring will be short?

Chapter 11 Section 3, Pgs. 270-273 and Chapter 14, Pg. 344 Mendelian Genetics Chapter 11 Section 3, Pgs. 270-273 and Chapter 14, Pg. 344 Objective: Students will A) Summarize Mendel’s Law of Independent Assortment B) Identify how dihybrid crosses support independent assortment Complete punnett squares for two trait crosses Summarize Mendel’s three laws

Mendel’s Laws 1. Law of Dominance 2. Law of Segregation 3 Mendel’s Laws 1. Law of Dominance 2. Law of Segregation 3. Law of Independent assortment

A) Summarize Mendel’s Law of Independent Assortment Alleles for different traits are distributed to gametes (& offspring) independently of one another. Ex. Tall plants are not always found with yellow seeds This law can be illustrated using dihybrid crosses – two trait crosses of hybrids (TtYy).

B) Identify how dihybrid crosses support independent assortment TtRr X TtRr Each parent can produce 4 types of gametes. Use FOIL from math to ID gametes. First, Outer, Inner, Last TR, Tr, tR, tr Cross is a 4 X 4 with 16 possible offspring.

B) Identify how dihybrid crosses support independent assortment Traits: Seed shape & Seed color Alleles: R round r wrinkled Y yellow y green Mendel’s Questions: Does round always come with yellow and does wrinkled always come with green? Are traits connected? RrYy x RrYy RY Ry rY ry RY Ry rY ry All possible gamete combinations

B) Identify how dihybrid crosses support independent assortment B) Identify how dihybrid crosses support independent assortment. Place gametes of parents from foil on the “Big Square”. Parent #1 gametes on the top. Parent #2 gametes on the left side. RY Ry rY ry RY Ry rY ry RY Ry rY ry RY Ry rY ry

B) Identify how dihybrid crosses support independent assortment Phenotypic ratio: 9:3:3:1 Round/Yellow: 9 Dom/Dom Round/green: 3 Dom/Rec wrinkled/Yellow: 3 Rec/Dom wrinkled/green: 1 Rec/Rec RY Ry rY ry RRYY RRYy RrYY RrYy RRyy Rryy rrYY rrYy rryy

What Do the Peas Look Like? Obj. B) Identify how dihybrid crosses support independent assortment

A. TG, TG, tG, tG B. tY, tY, tY, tY C. TR, Tr, TR, Tr Obj. C) Complete punnett squares for two trait crosses Gamete identification practice. Given the following genotypes of a parent, identify the four gametes they will produce. TtGG ttYY TTRr A. TG, TG, tG, tG B. tY, tY, tY, tY C. TR, Tr, TR, Tr

TP TTPP TTPP TTPP TTPP Tp TTPp TTPp TTPp TTPp tP TtPP TtPP TtPP TtPP Obj. C) Complete punnett squares for two trait crosses Complete the following cross: T = tall, t = short P = purple flowers, p = white flowers Cross a Homozygous tall purple-flowered pea plant with a completely heterozygous pea plant TTPP x TtPp TP TP TP TP TP TTPP TTPP TTPP TTPP Phenotypic ratio: 100% Tall/Purple Tp TTPp TTPp TTPp TTPp tP TtPP TtPP TtPP TtPP tp TtPp TtPp TtPp TtPp

Obj. D) Summarize Mendel’s three laws PARENT CROSS OFFSPRING P Gen TT x tt tall x short 100% Tt tall DOMINANCE SEGREGATION F1 Gen Tt x Tt tall x tall 75% tall 25% short Dihybrid Cross RrGg x RrGg round & green x round & green INDEPENDENT ASSORTMENT 9/16 Dom/Dom 3/16 Dom/Rec 3/16 Rec/Dom 1/16 Rec/Rec

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Understanding Check: Two Trait Crosses: T = Tall, t = Short R = Round, r = wrinkled Identify how many offspring are predicted to possess each of the 4 possible phenotypes. You must show your work. Cross a TTrr X ttRR Cross parent 1 who is heterozygous for both traits with parent 2 who is short and wrinkled.