Mendelian Genetics

Gregor Mendel was a monkwas a monk Studied mathematicsStudied mathematics Lived in Austria in the mid 1800’sLived in Austria in the mid 1800’s -First to conduct genetic experiments

MENDEL’S LEGACY Mendel was put in charge of the monastery garden, where he began his experiments with plant genetics.Mendel was put in charge of the monastery garden, where he began his experiments with plant genetics.

Mendel studied inherence in pea plants Peas are easy to cross pollinate.Peas are easy to cross pollinate. Traits easy to observe.Traits easy to observe. Many generations in short period of time.Many generations in short period of time.

Traits studied Seed shape, colorSeed shape, color Pod shape, colorPod shape, color Flower color and position on stemFlower color and position on stem

Hand pollination Anthers – male part of plant the carries pollenAnthers – male part of plant the carries pollen Stigma – female part of plantStigma – female part of plant Self pollination – same flowerSelf pollination – same flower Cross –pollination – different plantCross –pollination – different plant

Mendel’s Experiments Mendel self- pollinated plants until they bred true: pure strainsMendel self- pollinated plants until they bred true: pure strains P generation (parent)P generation (parent) F1 generation – 1 st crossF1 generation – 1 st cross F2 generation - 2 nd crossF2 generation - 2 nd cross The short trait disappeared in the F1 generation, but reappeared in the F2

A pair of “factors” determines a trait. (alleles) Dominant: if one factor is present, the trait will show (AA or Aa) Recessive: will only show if dominant factor is not present (aa) Mendel’s Conclusions Yellow seeds are dominant to green seeds

Alleles for the same trait are separated during gamete formation. –Each gamete has only 1 allele for each trait ex: either purple or white flower color. Law of segregation

Law of independent assortment Alleles for different traits end up in different gametes during meiosis –traits sort independently of each other. Ex: Alleles for seed color and seed texture are sorted independently of each other. (The chromosomes sort independently)

White board Review 1.What is a dominant trait? 2.What is the law of segregation? 3.What is the F 1 generation?