Mendelian Genetics

Let’s Review How are traits coded? Where are genes located? Chromosomes are composed of what macromolecule?

Father of Genetics Gregor Mendel pea-plants-helped-us-understand-genetics- hortensia-jimenez-diaz

Mendel’s Three Laws

Mendel' Law of Segregation The two copies of the gene separate during meiosis.

Mendel' Law of Dominance one factor in a pair of traits dominates the other in inheritance unless both factors in the pair are recessive.

Mendel' Law of Independent Assortment The alleles of different genes separate independently of each other during meiosis

Vocabulary

Genotype Genetic makeup Two alleles inherited for a particular trait Ww

Phenotype Physical trait of a gene Wrinkled pea

Allele one of two or more alternative forms of a gene W,w

Gene Segment of DNA found on a chromosome

Punnett Square a diagram that is used to predict an outcome of a particular cross

Monohybrid Cross Cross between two organisms with different alleles for the same gene.

Dihybrid Cross Cross between two organisms with different alleles for the two genes.

Homozygous Two of the same alleles for a gene. WW – homozygous dominant ww – homozygous recessive

Heterozygous Two different alleles for a gene. Ww

Hybrid Organism that has two different alleles for a gene. Heterozygous Ww

Purebred Organism that has two of the same alleles for a gene. Homozygous WW ww

Dominant Allele that “hides” the other allele Not necessarily the most common allele Use the first letter of the dominant trait for the Punnett square W

Recessive Allele that is “hidden” by the other allele Must have two of the recessive allele for the trait to show up Lower case letter in a punnett square w

P Generation Parent Generation Pure bred or true- breeding

F1 Generation Offspring of P generation Hybrid generation

F2 Generation Offspring of a cross between two of the F1 generation

Let’s Practice Using the Smart Board