Bell Ringer What does NOT happen between Meiosis I and Meiosis II that reduces the number of chromosomes? When animals reproduce, which process replicates their chromosomes? In one sentence, describe what happens during Meiosis I.

Mendelian Genetics and Punnett Squares Biology February 13, 2014

Gregor Mendel Austrian monk who studied garden peas. Noticed certain patterns as he observed each generation. Began experimenting by crossbreeding. crossbreeding: mating two organisms to produce offspring

Mendel’s Traits Mendel studied seven different traits: height (tall/short) flower color (purple/white) flower position (axial/terminal) seed color (yellow/green) seed shape (round/wrinkled) pod color (green/yellow) pod shape (inflated/constricted)

HUMAN TRAIT INVENTORY

Describe the two pea plants. Height: Flower Color: Flower Position: : Dwarf Height: Flower Color: Flower Position: : Tall : Purple : White : Axial : Terminal

Gregor Mendel’s Experiments 1) chose a trait to examine 2) cross-pollinated members of the parent (P) generation 3) counted the results in the first filial (F1) generation 4) cross-pollinated members of the F1 generation 5) counted the results in the second filial (F2) generation

Mendel’s Experiments P Generation: Purebred Tall x Purebred Short Result (F1 Generation): All Tall F1 Generation: Tall x Tall Result: (F2 Generation) 75% Tall, 25% Short

Gregor Mendel’s Conclusions traits are inherited from one’s parents. traits follow specific laws as they are passed, resulting in predictable ratios ex. heterozygous tall x heterozygous tall **** T t 75% Tall 25% Short T TT Tt t Tt tt

Genetics Vocabulary : a piece of DNA that codes for a trait gene: ex. height : a piece of DNA that codes for a trait

Genetics Vocabulary allele: : different forms of the same gene each individual has two alleles for each trait one allele comes from each parent ex. T or t dominant allele: recessive allele: : different forms of the same gene : always expressed when present : expressed when no dominant is present

Genetics Vocabulary : combination of alleles for a trait genotype: homozygous: ex. TT or tt heterozygous: ex. Tt phenotype: ex. tall or short : combination of alleles for a trait : both alleles are the same : both alleles are different : physical characteristic of an organism

Trait: pea plant height Genotype vs Phenotype Trait: pea plant height Genotype Phenotype Example TT homozygous tall Tt heterozygous tall tt homozygous dwarf

Review Directions: Identify the following as a trait/gene, an allele, a genotype, or a phenotype. Y Ww Flower Color Yellow Seeds TT Flower Position t Dwarf Plant Height Purple Flowers allele trait/gene genotype allele trait/gene phenotype phenotype trait/gene genotype phenotype

PRACTICE!

Mendel’s Laws 1. The Law of Segregation: the two alleles that make up the genotype separate during meiosis so that each gamete only has one copy T \ T TT \ T \ t Tt \

Mendel’s Laws 2. The Law of independent assortment: alleles of different genes assort independently TW \ TtWw Tw \ tW \ tw \

Mendel’s Laws 3. The Law of Dominance: if a dominant allele is present in the genotype, it will be expressed in the phenotype Tall (TT) Tall (Tt) Dwarf (tt)

What type of car is this? GAS + ELECTRIC Hybrid = MIXED FROM 2 PARTS

Monohybrid Cross ONE MIXED MATING 1 Pair of Traits Mom + Dad

Possible Offspring inside boxes Punnett Square: a diagram used to predict the outcome of a particular genetic cross T t Father’s Genotype TT Tt T Mother’s Genotype T Possible Offspring inside boxes

Multiplication Table 1 2 3

Multiplication Table 1 2 3 1 2 3 4 6 9

Possible Offspring inside boxes Punnett Square: a diagram used to predict the outcome of a particular genetic cross T t Father’s Genotype TT Tt T Mother’s Genotype T Possible Offspring inside boxes

tall (T) is dominant to short (t) Genotype 50% Tt 50% tt 1:1 Phenotype 50% tall 50% short 1:1 heterozygous tall t Tt tt hetero tall homo short homozygous short t Tt tt hetero tall homo short

tall (T) is dominant to short (t) Genotype 25% TT 50% Tt 25% tt 1:2:1 Phenotype 75% tall 25% short 3:1 heterozygous tall T TT Tt homo tall hetero tall heterozygous tall NOTE: All monohybrid Crosses of heterozygous of parents produce these ratios. t Tt tt hetero tall homo short

purple flowers (W) are dominant to white (w) Genotype 100% Ww Phenotype 100% purple homozygous purple w Ww Ww hetero pur hetero pur homozygous white w Ww Ww hetero pur hetero pur

purple flowers (W) are dominant to white (w) Genotype 50% Ww 50% ww 1:1 Phenotype 50% purple 50% white 1:1 heterozygous purple w Ww ww hetero pur homo white homozygous white w Ww ww hetero pur homo white

Review What are genes? What’s a genome? How many copies of each gene do we each inherit? What is probability? Organisms that have two identical alleles for a particular trait or what? What do letters inside a Punnett square represent? If a tree is homozygous recessive for height (T, t), how would its alleles be represented? When Mendel crossed a tall plant with a short plant, the F1 plants inherited what?

Review Which principle states that during gamete formation, genes for different traits separate without influencing each other’s inheritance? If you flip a coin 67 times, what’s the probability that it will come up heads? If two people that cross their eyes (E) marry and have a child that cannot cross their eyes (e), what are the genotypes of the parents? Why? Who or what does Gregor Mendel’s principles of genetics apply to?

Remember, Ch. 6-3,4,5,6 Vocabulary Quiz Tomorrow! Independent Practice Complete Monohybrid Cross worksheet (Will be checked during Bell Ringer tomorrow. NO LATE WORK ACCEPTED) Review Vocabulary (All words are on Quizlet) Remember, Ch. 6-3,4,5,6 Vocabulary Quiz Tomorrow!