Take out a sheet of paper, and put your name on it.

1. Who is known as the father of genetics? A. Felix Mendelssohn B. Gregor Mendel C. Dr. Reginald Punnett D. Albert Einstein

2. What did this person study? A. rabbits B. Trees C. Dogs D. Pea plants

3. The offspring of a pure, true- breeding generation are called: A. F1 generation B. F2 generation C. P generation D. Q generation

4. Different forms of a single gene are called A. Traits B. Alleles C. Phenotypes D. Genotypes

5. Outward expression of traits is a A. genotype B. Trait C. Phenotype D. Recessive

6. Which of these is heterozygous? A. TT B. tt C. TZ D. Tt

7. Which of these will NOT show brown eyes, if B is dominant for brown? A. BB B. Bb C. bb D. bB

8. What gametes will be formed from a plant with the genotype of Yy? A. Y B. y C. Yy D. Both A and B

9. The previous question described Mendel’s law of A. Segregation B. Independent assortment C. Hybrids D. dominance

10. Fill in the Punnett square showing the cross of Bb and Bb:

11. What is the ratio of brown eyes to blue eyes, if brown is dominant? (from #10) A. 3:1 B. 1:3 C. 4:1 D. 1:4

12. What is the genotype ratio from the cross in #10? A. 3:1 B. 1:2:1 C. 2:2 D. 1:3

When you’re done with the traits chart: Work on Drawing the “senior portrait” for your offspring! Make sure to include every trait, write the offspring’s name, and the name of the parents (you!) Work on the questions in the packet

Mendelian Genetics MAIN IDEA: Mendel explained how a dominant allele can mask the presence of a recessive allele.

“Father of Genetics” Gregor Mendel – Austrian monk and plant breeder Studied inheritance in pea plants Pea plants – usually self-fertilize, but he cross-pollinated to study traits

Mendel’s work Pea plants have only 2 forms of each trait True-breeding plants produce offspring with only one form of each trait – ex: always green seeds P  F1  F2

Do Now: Take out Simple Genetics Problems packet and complete it

Parental (P) Generation Mendel crossed 2 true-breeding plants with opposite traits. Ex: green seed X yellow seed (Only monitor one trait at a time – others the same – controlled)

First Filial Generation (f1) Offspring of P generation 100% showed only ONE of the parent’s traits. Ex: yellow seeds X green seeds – produced ALL yellow seeds Where did the green seeds go?

Second Filial Generation (F2) Self-pollinated plants from F1 Results: 6022 yellow seeds and 2001 green seeds 3:1 ratio Studied 7 traits total, all with same results

Mendel’s Conclusions Must be 2 forms of each trait Each form called an allele – alternative form of one gene Dominant vs. recessive alleles Homozygous vs. heterozygous (hybrid) Genotype vs. phenotype

Law of Segregation During meiosis, 2 alleles for each trait separate

Answer This! Parent plants: YY and yy (yellow=dominant, green=recessive) How do we set up the cross? What genotype possibilities are there for the offspring? What are the resulting ratios for genotype and phenotype? Repeat for the F1 generation.

Law of Independent Assortment During meiosis and gamete formation, alleles are distributed randomly. Genes on separate chromosomes sort independently during meiosis.

Do Now What are Mendel’s 2 laws of genetics? What is the probability of flipping a coin, and it landing on heads? What is the probability of flipping 2 coins, and both are heads? What is the probability of flipping 2 coins, and getting heads & tails in any order?

Example Alleles in parent cell: TtGg What are the possible gametes from this parent? Use FOIL to find out!

FOIL TtGg F = first  TtGg = TG O = outer  TtGg = Tg I = inner  TtGg = tG L = last  TtGg = tg Possible gametes: TG, Tg, tG, tg There’s an equal chance of each gamete combination (1/4 chance)

Monohybrid vs. Dihybrid (Don’t Copy) Monohybrid – cross only one trait Dihybrid – cross 2 traits (dihybrids are heterozygous for both traits)

Cross 2 dihybrids TtGg X TtGg Set up a 16 box Punnett Square Write the possible gametes across the top and side Fill in the offspring Determine the phenotype ratio

Probability Punnett squares give PROBABLE (predicted) outcomes Actual data MAY NOT always match the predicted outcomes

Example When you flip a coin, what is the chance it will land on heads? If you flip a coin 10 times in a row, how many times would you predict it to land on heads?

Rules of Probability A larger sample size will give results more accurate to predicted outcome than a smaller sample. Ex: Mendel used thousands of plants! Only using a few would not have been as accurate.

Rules of Probability In determining the probability of 2 independent events occurring at the same time, you multiply the probability of each. Ex: The probability of a coin landing heads up is ½. The probability of 2 coins landing heads up at the same time is ½ x ½ = ¼.

Rules of Probability The probability of an event occurring any one of several possible ways is the sum of their individual probabilities.

Rules of Probability Example: If you flip 2 coins (a nickel and a penny), there is a ¼ chance of the nickel being heads and the penny being tails. There is also a ¼ chance of the opposite. There is a ½ chance (1/4 + ¼) of one coin being heads and one being tails.

Probability Examples What’s the chance of parents having a girl as opposed to a boy? If a couple has 2 children, what’s the chance of them both being girls? What’s the chance of them both being boys?

Probability Examples If a couple has 3 children, what’s the chance of them all being girls? If a couple has 2 children, what’s the chance of the oldest being a boy and the youngest being a girl? What’s the chance of them having a boy and a girl in any order?

Do Now What is the probability of a couple having a girl? What is the probability of a couple having 2 girls in a row? Set up the following Punnett Square: FFTt x Fftt

10.3: Gene Linkage and Polyploidy MAIN IDEA: Crossing over of linked genes is a source of genetic variation.

Genetic Recombination When new combinations of genes are made by: Crossing over Independent assortment Occurs during meiosis

Independent Assortment Number of possible gene combinations = 2 n n = # of chromosome pairs Ex: how many gene combinations are possible in an organism with 3 gene pairs?

After Fertilization… Number of possible gene combinations = 2 n x 2 n How many possible gene combinations are possible in an organism with 3 chromosome pairs AFTER fertilization? Crossing over increases possibilities even more!

Gene Linkage Each chromosome has many genes If genes are close together on one chromosome, they are linked Linked genes DO NOT segregate independently during meiosis Separation only happens during crossing over; more likely in far apart genes

Chromosome Map Shows order of genes on a chromosome Distance between genes – estimated by how often crossing over occurs between them More crossing over = farther apart

Figure out the Order GenesFrequency of C.O. D-F15% G-D2% E-G8% E-D10% G-F17% E-F25%

Polyploidy Cells have one or more extra sets of chromosomes LETHAL in humans Seen in some animals (earthworms, goldfish) and flowering plants Useful to make bigger, stronger food plants (wheat, oats, strawberries)

DO NOW Which of these is NOT equal to the others? 25% 1:3 1:4 1/4