What is Heredity? _____________- is the Study OF Genes/Heredity

Chromosome Review Humans have 46  23 pairs Each pair consists of one chromosome from mom & one from dad Types of Chromosomes Sex chromosomes - 23rd pair ____________

__________ Sex Chromosomes

Genes & Alleles Gene – sequence of DNA coding for a protein  determines a trait     _________– alternate/different forms of a gene Example: Height = Tall or short      

Who was Gregor Mendel? The Father Of Modern__________ Used pea plants to study the inheritance of ________

Mendel’s Discoveries: _____________Alleles - same 2 alleles _________Alleles - 2 different alleles

Dominant Allele – always________ Recessive Allele - only expressed if homozygous _________

Principle of _________– some alleles are dominant and others are__________ Phenotype - physical expression/characteristics of the gene __________– genetic makeup of an organism

Mendelian Laws: Law of ___________– each individual carries a pair of alleles for each trait and these alleles will separate to form gametes Law of Independent ___________- each trait will separate independently of all other traits.

Punnett Squares

Punnett Squares Show possible gene combinations – hybrids Principle of_______________

How to use: _____________Cross = Aa x Aa A = Freckles a = No Freckles Genotype ratio: 1:2:1 AA = 1 Aa = 2 aa = 1 Phenotype ratio: 3:1 With freckles = 3 No freckles = 1

Column & Row Letters They represent _________from one of the parents

Dihybrid Cross: RrYy x RrYy R = Smooth r = Wrinkled Y = Yellow y = Green Use the _________method (first, outer, inner, last) to produce gamete combinations Female: RrYy Male: RrYy Gametes Gametes RY RY Ry Ry rY rY ry ry

_____________Cross Phenotype ratio: 9:3:3:1 Smooth & Yellow = 9 Wrinkled & Yellow = 3 Smooth & Green = 3 Wrinkled & Green = 1