Chapter 10.1: Mendel

Gregor Mendel Father of genetics Studied heredity Passing on of traits from parent to offspring

Gregor Mendel cont… Genetics—the study of heredity

Gregor Mendel cont… Traits—characteristics that are inherited Ex: Height, Hair color, breast cancer

Gregor Mendel cont… Mendel studied pea plants Reproduce sexually Have two sex cells (gametes) One male, one female

Garden peas cont… Both sex cells in same flower Male sex cell = pollen Female sex cell = ovule

Garden Peas Cont… Pollination—how plants reproduce Transfer pollen to ovule Fertilization—combining the male and female sex cells Result = seed (baby plant)

Garden Peas Cont… Plants usually self-pollinate Male and female gametes of same flower combine Mendel used cross pollination Male of one flower combines with female of another flower

Punnett Squares Hybrid—a child whose parents had different traits Ex: Dad is tall and mom is short Kid is hybrid for height

Monohybrid Cross Punnett square for one trait Ex: Tt x Tt Results = 3:1 ratio

Monohybrid Cross cont… Traits are found on genes which make up chromosomes Alleles—different genes Ex: T or t (T = tall, t = short)

Rule of Dominance All humans have both dominant and recessive alleles Dominant—trait that shows up Ex: T = tall or B = brown hair Recessive—trait that is normally hidden Ex: t = short or b = blonde hair

Rule of Dominance cont. Only time you see a recessive trait is when both parents give you the recessive Ex: tt = short or bb = blonde hair

Law of Segregation Parents don’t control what genes they give their kids

Vocabulary Phenotype—in words, what your traits are Ex: Tall, short, has breast cancer

Vocab cont… Genotype—in letters, what your traits are Ex: TT, Tt, tt

Vocab cont… Homozygous—2 alleles for a trait are the same Could be dominant = TT Could be recessive = tt

Vocab cont… Heterozygous—2 alleles for a trait are different Only dominant = Tt

Law of Independent Assortment All traits are inherited separately Ex: All blonde hairs don’t have blue eyes

Probability The likelihood of something happening Ex: Chances of having a boy vs. a girl = 50%