Date: February 29, 2016 Aim #57: How are traits inherited? HW: 1)Human Fetus Development Lab due Wednesday 2)Human Phys. Unit 7a Packet due next Friday (March 4 th ) Do Now: Warm-Up Notebook DateTitle of Activity Page # **No Warm-Up Today **

Aim #57: How are traits inherited?

1) Traits Traits Traits are a person’s physical characteristics. Ex: Eye color, hair color, etc…

2) What determines our traits? Genes found on chromosomes (DNA) determine your traits. Genes appear as dark bands on the chromosome.

46 Why do we have two of each chromosome? HOMOLOGOUS CHROMOSOMES – pairs of chromosomes, one from each parent. SEX CHROMOSOMES 3) Chromosomes AUTOSOMES

Inheritance During Fertilization each parent’s sex cell contributes half the chromosomes. 23

Offspring will receive two copies of each chromosome, one from dad and one from mom. 4) Results of Fertilization

Gregor Mendel “Father of Genetics” Characteristics of offspring were the result of inheriting “factors” from parents

Used pea plants because… Easy to grow Quick germination time Can control pollination Traits are easy to observe

5) Alleles The different forms of a gene. They can be dominant or recessive GENE FOR PEA COLOR HAS TWO ALLELES: GREEN & YELLOW

6) Genes can be DOMINANT & recessive Dominant genes are indicated with a CAPITAL (RR) letter, while recessive genes are indicated with lowercase (rr) letters. Dominant alleles will be seen over the recessive genes.

7) Genes come in different forms MomDad Hair Color Traits B = Black Hair b = Red Hair BB bb Bb Black Red Black Which gene is dominant? Black Hair

Dominant or recessive? RR – (Dominant) Rr – (Dominant – R show through) rr – (recessive) R = red r = white

8) Genotype determines phenotype Genotype: actual types of genes on the chromosomes (RR, Rr, rr) Phenotype: physical appearance

9) When will the recessive allele show in the phenotype? Two recessive alleles must come together (one from each parent). In other words, a recessive trait will only appear when two lowercase letters are together.

10) Heterozygous vs. Homozygous RR or rr Homozygous- the two alleles are the same Heterozygous- the two alleles are different Rr

Date: March 1, 2016 Aim #57: How are traits inherited? HW: 1)Complete Worksheet?? 2)Human Fetus Development Lab due Wednesday 3)Human Phys. Unit 7a Packet due next Friday (March 4 th ) Do Now: Warm-Up Notebook DateTitle of Activity Page # 3/1Know Your Genetics Vocabulary98

Basic Rules for Genetics: 1)Two alleles (mom & dad) code for one trait. 2) DOMINANT alleles will be seen over recessive alleles. 3) DOMINANT alleles are written with capital letters. 4) Recessive alleles are written with lowercase letters.

11) Mendel’s Laws 1)Law of Dominance- dominant alleles will be seen over recessive alleles. 2)Law of Segregation- during the formation of gametes, the two alleles responsible for a trait separate from each other. 3)Law of Independent Assortment- alleles for different traits are sorted independently from each other.

Law of Dominance Heterozygous individuals will express the phenotype of the dominant allele Example: Tt will be a tall plant

Law of Segregation and Recombination

Law of Independent Assortment Traits are inherited independently of each other if they are on different chromosomes Example: seed color and seed shape

Punnett Squares b = white fur Male Female

How can we predict genotypes and phenotypes of offspring? AAAa aa

Amoeba Sisters Monohybrid Cross (Mendelian)

Summary Find the percentages for genotypes and phenotypes for each cross. 1.In guinea pigs, black coat color is dominant over to brown coat color. Cross a black male guinea pig (Bb) with a brown female (bb).

Summary Find the percentages for genotypes and phenotypes for each cross. 2. Cross a black male (Bb) with a black female (BB).

Summary Find the percentages for genotypes and phenotypes for each cross. 3. Cross 2 tall pea plants with the genotypes TT and Tt.

Summary 1.In guinea pigs, black coat color is dominant over brown coat color. The genotype of a guinea pig is BB. What color is the coat color of the mom and dad? b)If the genotype of the guinea pig is bb, what is the coat color of the mom and dad?

Monohybrid Cross Vs. Dihybrid Cross Rr x Rr RrTt x RrTt

12) Testcross You breed an individual of unknown genotype, but dominant phenotype with a homozygous recessive individual P = purple p = white

13) Exceptions: Codominance Both alleles are expressed in the phenotype. Example: Blood Type Heterozygotes will express both traits

14) Exceptions: Intermediate Inheritance The heterozygotes have a phenotype that is intermediate between the phenotypes of the two homozygotes P = Parent F 1 = 1 st generation F 2 = 2 nd generation