Gregor Mendel: Father of Genetics • Mendel conducted experiments using garden pea plants • Cross pollinated flowers and observed traits in offspring BIO.B.2.1.1 Describe & predict observed patterns of inheritance (i.e. dominant, recessive, codominance, incomplete dominance, sex-linked, polygenic and multiple alleles). Kindlin BIO.B.2.2 Mendelian Genetics PPT 2016

Pea Plant Traits

Mendel’s Experiment Mendel developed a true-breeding parent generation, P generation. True-breeding purple flowered plants always produce purple flowered offspring. Mendel crossed purple & white flowered plants. The offspring are called the first filial generation, F1 generation. They all had purple flowers. The offspring of the F1 generation is called the F2 generation.

Mendel’s Observations The observed trait is called dominant. The dominant trait is represented with uppercase letters. The hidden trait is called recessive. The recessive trait is represented with lowercase letters.

Genotype Determines Phenotype! The physical appearance is called phenotype. For each trait, we have two alleles, or versions of a gene. We get one allele from each parent. Our set of alleles determines our genotype. PP = genotype Purple = phenotype pp = genotype white = phenotype

What is a Gene? A gene is the basic unit of heredity. A gene is a segment of DNA on a chromosome that describes how to make a certain protein. Each gene is located at a specific locus on the chromosome. A genome is all of the genetic information for an organism.

What will be the genotypes of the offspring? ______ ______

Same or Different Alleles? If both alleles are the same they are called homozygous. Homozygous Dominant = PP Homozygous Recessive = pp If the alleles are different it is called heterozygous. Heterozygous = Pp

TT x Tt Tt x Tt

Law of Independent Assortment Pairs of alleles separate independently during meiosis as long as they are on different chromosomes or far apart on the same chromosome. Ex. Seed shape and seed color

Non-Mendelian Patterns of Inheritance: Codominance Incomplete Dominance Sex-linked Polygenic Multiple Alleles

Codominance Produces Offspring with Both Phenotypes Expressed

Incomplete Dominance Produces a Blending in the Phenotype

Colorblindness is Sex-Linked

Pedigree shows the typical inheritance pattern found in red-green color-blindness

Sickle Cell Anemia is Sex-Linked

Polygenic Traits Many genes code for a single trait. You typically see a wide variety of phenotypes as a result. Examples: Skin color, Hair color, Eye color, Human height

Kindlin BIO.B.2.2 Mendelian Genetics PPT 2016