Mendel’s Laws of Mendel’s Laws of HeredityHeredity

Why we look the way Why we look the way we look...we look...

Mendel used Mendel used peas...peas...

They reproduce They reproduce sexuallysexuallyThey have two distinct, They have two distinct,

malemale and and femalefemale, sex cells , sex cells called called gametesgametes

Their Their traitstraits are easy to are easy to isolateisolate

Mendel Mendel crossedcrossed them them

FertilizationFertilization - the uniting - the uniting of male and female of male and female gametesgametes

CrossCross - combining - combining gametes from parents gametes from parents with different traitswith different traits

What Did Mendel What Did Mendel Find?Find?

He discovered different He discovered different lawslaws and and rulesrules that that explain factors affecting explain factors affecting heredityheredity..

Rule of DominanceRule of Dominance

The trait that The trait that is observedis observed in the offspring is the in the offspring is the dominant trait dominant trait (uppercase)(uppercase)

The trait that The trait that disappears disappears in the offspring is the in the offspring is the recessive trait recessive trait (lowercase)(lowercase)

Law of SegregationLaw of Segregation Genes appear in pairs on Genes appear in pairs on

homologous chromosomeshomologous chromosomes SEPARATEDSEPARATED when gametes are when gametes are

formedformed Recombine during fertilizationRecombine during fertilization

Law of Independent Law of Independent AssortmentAssortment The genes for different traits are The genes for different traits are

inherited independentlyinherited independently of each of each other.other.

Homologous chromosomes move Homologous chromosomes move randomlyrandomly to gametes to gametes

Explains why siblings look differentExplains why siblings look different

Monohybrid Vs Monohybrid Vs DihybridDihybrid

Monohybrid CrossMonohybrid Cross - crossing - crossing parents who differ in only parents who differ in only one trait one trait ((AAAA with with aaaa))

Dihybrid CrossDihybrid Cross - crossing - crossing parents who differ in parents who differ in two two traits traits ((AAEEAAEE with with aaeeaaee))

Bozeman Tutorial

http://www.youtube.com/watch?v=Y1PCwxUDTl8

Incomplete Dominance - Incomplete Dominance - BlendBlend

Codominance - Both showCodominance - Both show

Sex-LinkedSex-Linked

Sex-LinkedSex-Linked

Multiple Alleles - Blood Multiple Alleles - Blood TypeType

Multiple Alleles - Blood Multiple Alleles - Blood TypeType

Dihybrid Cross - 2 traitsDihybrid Cross - 2 traits