Mendelian Genetics

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

Who developed the current ideas of inheritance? Gregor Mendel Father of Genetics Experiments used ~ 29,000 Pea Plants and the characteristics of the plants

Let’s look at Mendel’s experiments and the results.

Experiment 1 Read the description of the experiment on the graphic organizer. Answer the question and be prepared to share.

Experiment 1 Actual Results 100 % Tall Plants Answer the questions on the graphic organizer and be prepared to share.

Experiment 2 Mendel crossed the offspring of the F1 generation. Answer the question on the graphic organizer and be prepared to share.

Experiment 2 – Actual Results Look at the results on your desk Answer the question on the graphic organizer and be prepared to share.

How would math show a pattern? Percentage of a trait Total number of plants = Divide number of tall plants by total number of plants * 100 Divide number of short plants by total number of plants * 100 Ratio between both traits Number of tall plants / number of short plants Number of short plants / number of short plants Round up Do the calculations for all of Mendel’s data.

Mendel’s Conclusions based on experiment results

Mendel’s Three Laws

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 Segregation The two copies of the gene separate during meiosis.

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

Gene Locus Specific location of a gene 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

Review of Concepts pea-plants-helped-us-understand-genetics- hortensia-jimenez-diaz

Let’s Practice Punnett Squares Using the Smart Board