1/26 Daily Catalyst Pg. 73 Inheritance Patterns 1. In cats, long hair is recessive to short hair. A true-breeding (homozygous) short-haired male is mated to a long-haired female. What will their kittens look like? 2. Define the law of segregation.

1/26 Daily Catalyst Pg. 73 Inheritance Patterns 1. In cats, long hair is recessive to short hair. A true-breeding (homozygous) short-haired male is mated to a long-haired female. What will their kittens look like? S S Ss Ss Recessive: long hair ss Dominant: short hair SS s 100% are short haired kittens Ss Ss

1/26 Daily Catalyst Pg. 73 Inheritance Patterns 2. Define the law of segregation. Two alleles separate during gamete formation and end up in different gametes. (BB B and B) Law of independent assortment states that each PAIR of alleles separate from OTHER PAIRS of alleles during gamete formation (BB and Tt  BT, Bt, BT, Bt)

1/27 Daily Catalyst Pg. 73 Inheritance Patterns 1. 2. 3.

1/27 Class Business Pg. 73 Inheritance Patterns Quiz #18 on Thursday Inheritance patterns, blood types, and genetic disorders Genetic test on Tuesday, February 3rd Study guide due test day Notebook check Come see me for tutoring! Khan Academy and Bozeman Biology have great videos

1/27 Agenda Pg. 73 Inheritance Patterns 1. List the three main sources of genetic variation. 2. Describe the 9:3:3:1 rule. 3. Two parents have a genotype of AaHH and aaHh. The dominant allele is attached earlobes (A) and the recessive allele is detached earlobes (a). The other dominant trait is hair (H) and the recessive allele is no hair (h). What are the genotypes AND phenotypes of the F1 generation.

1/27 Agenda Pg. 73 Inheritance Patterns 1. List the three main sources of genetic variation. Meiosis, random fertilization, and independent assortment. 2. Describe the 9:3:3:1 rule. 9/16 will be dominant for BOTH traits 3/16 are dominant for one trait and recessive for the other 3/16 are recessive for one trait and dominant for the other 1/16 are recessive for both traits 3. Two parents have a genotype of AaHH and aaHh. The dominant allele is attached earlobes (A) and the recessive allele is detached earlobes (a). The other dominant trait is hair (H) and the recessive allele is no hair (h). What are the genotypes AND phenotypes of the F1 generation.

1/26 Agenda Pg. 73 Inheritance Patterns Daily Catalyst Class Business Quiz #17 Dihybrid video clip Example

https://www.youtube.com/watch?v=Y1PCwxUDTl8

The Law of Independent Assortment A true-breeding tall. Purple-flowered pea plant (TTPP) is crossed with a true –breeding dwarf, white-flowered plant (ttpp). A. What is the phenotype of the f1 generation? B. What is the genotype of the F1 generation? C. What four types of gametes are formed by F1 plants? D. Fill in the following Punnett Square to show the offspring of the F2 generation. Shade each phenotype a different color so you can see the ratio of offspring. E. List the phenotypes and ratios found in the F2 generation. F. What is the ratio of tall to dwarf plants? Of purple to white flowered plants? ( note that alleles for each trait segregate as in a monohybrid cross)

A. tall purple plants B. TtPp C. TP, Tp, tP, tp D. E. 9 tall purple: 3 tall white:3 dwarf purple: 1 dwarf white F. 12:4 or 3:1 tall to dwarf; 12:4 or 3:1 purple to white

Pg. 72

The Law of Independent Assortment Key Point #7: The Law of Independent Assortment Every pair of allele for each trait segregate independently in the formation of gametes Dihybrid crosses with both partners heterozygous follow the 9:3:3:1 rule

The Law of Probability Key Point #8: What is the probability of rolling a three on a dice? One out of six What is the probability of rolling a 3, 5, and 6 on a dice? Three out of six

Pg. 73 What happens when alleles are NOT completely dominant or recessive, or when a single gene produces multiple phenotypes….

The Spectrum of Dominance Alleles can show different degrees of dominance and recessiveness in relation to each other. This is called the spectrum of dominance. Key Point #1: Complete Dominance One allele is completely dominant over another allele The phenotypes of the hybrid and homozygous dominant look the same

The Spectrum of Dominance At the other end of the spectrum, is codominance. Key Point #2: Codominance Two alleles both affect the phenotype in different ways Example- blood types

Blood Types Example: human blood types (A, B, AB, O) Determined by the antigens (proteins) on the RBC’s Three alleles, iA, iB, i determine blood type A and B are codominant O is recessive

https://www.youtube.com/watch?v=KXTF7WehgM8 4:30

The Spectrum of Dominance Key Point #3: Incomplete dominance Neither allele is completely seen Red flowers crossed with white flowers create PINK flowers NOT BLENDING, the genotypes are still present Let me show you…

Recessively Inherited Disorders Key Point #4: Tay-Sachs Disease Autosomal recessive (aa) Common in Central European Jewish descent 1 out of 3,600 Due to geographical isolation ( in gene pool) High number of aa and Aa in the population Lacking the enzyme to breakdown fats in the brain

Grade Punnett square worksheet

1/27 Homework Read the following sections. Outline this section in your notes on page 74. I will check tomorrow. Recessively Inherited disorders Cystic fibrosis Sickle cell Mating of class relatives Dominantly inherited disorders