Mendelian Genetics

Gregor Mendel

Character and Trait

Alleles – different versions of a gene Alleles – different versions of a gene. Both genes code for flower color.

Need 2 Alleles to make a trait

One from EACH parent Sperm AND Egg

True breed versus hybrid

Phenotype vs. Genotype Physical Trait vs. Gene allele type

Test Cross

Monohybrid Punnett

Dihybrid Punnett

Independent Assortment – See the different outcomes at the bottom Independent Assortment – See the different outcomes at the bottom? It was because of how they lined up on the midplane. Key Maternal set of chromosomes Possibility 1 Possibility 2 Paternal set of chromosomes Two equally probable arrangements of chromosomes at metaphase I Metaphase II Daughter cells Combination 1 Combination 2 Combination 3 Combination 4

Chance has NO memory.

Complete Dominance

Incomplete Dominance

Codominance

Multiple Alleles (multiple combinations) Codominance – See AB blood

Polygenic Traits

Pedigree Dominant Condition on the left Pedigree Dominant Condition on the left. Recessive Condition on the right.

Cystic Fibrosis

Sickle-Cell Disease

Simple Dominant Traits

Achondroplasia

Autosomes and linked genes

Genetic Recombination

Parental type (left) Recombinant type (right) What happened?

Sex –Linked Female See the two X chromosomes?

Sex-Linked Male See the one X chromosome?

Conception Some sperm have Xs and some have Ys Which one did you get from your father?

Pedigree of Color Blindness

Pedigree of Hemophila