What is today????What is today????

Ummmmmm, what is it???Ummmmmm, what is it??? VALEN-what?VALEN-what? Oh okayOh okay HAPPY VALENTINES DAY!!!!!!HAPPY VALENTINES DAY!!!!!!

• Candy, Candy, Candy, CandyCandy, Candy, Candy, Candy

At the end of class if you are At the end of class if you are AWESOME!!!!!AWESOME!!!!!

Mendel’s Laws of Mendel’s Laws of HeredityHeredity

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

Bell Ringer 2-14-13Bell Ringer 2-14-13

What is What is heredityheredity??The The passing passing on of on of

characteristics characteristics (traits)(traits) from parents to offspringfrom parents to offspring

GeneticsGenetics is the study of is the study of heredityheredity

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

QuestionsQuestions

What did Mendel cross?What did Mendel cross?What are What are traitstraits??What are What are gametesgametes??What is What is fertilizationfertilization??What is What is heredityheredity??What is What is geneticsgenetics??

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 Unit FactorsRule of Unit FactorsEach organism has two Each organism has two

alleles alleles for each for each traittrait–Alleles Alleles - different forms of - different forms of the same the same genegene

–Genes Genes - located on - located on chromosomes, they control chromosomes, they control how an organism developshow an organism develops

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

The two alleles for a trait The two alleles for a trait must separatemust separate when when gametes are formedgametes are formed

A parent randomly passesA parent randomly passes only oneonly one allele for each allele for each trait to each offspringtrait to each offspring

Law of Independent Law of Independent AssortmentAssortmentThe genes for different The genes for different

traits are traits are inherited inherited independentlyindependently of each of each other.other.

Questions...Questions...

How many How many allelesalleles are are there for each trait?there for each trait?

What is an What is an alleleallele??How many How many allelesalleles does a does a

parent pass on to parent pass on to eacheach offspring for offspring for eacheach trait trait

Questions...Questions...What do we call the trait that is What do we call the trait that is

observedobserved? ? What What casecase (upper or lower)(upper or lower) is it is it

written in?written in?What about the one that What about the one that

disappearsdisappears? ? What What casecase is it written in? is it written in?

Phenotype & Phenotype & GenotypeGenotype

PhenotypePhenotype - the way an - the way an organism organism lookslooks

–red hair or brown hairred hair or brown hair

genotypegenotype - the - the gene gene combinationcombination of an organism of an organism

–AAAA or or Aa Aa oror aa aa

Heterozygous & Heterozygous & HomozygousHomozygous

HeterozygousHeterozygous - if the two - if the two alleles for a trait are alleles for a trait are different different ((AaAa))

Homozygous Homozygous - if the two - if the two alleles for a trait are the alleles for a trait are the same same ((AAAA or or aaaa))

Dihybrid vs Dihybrid vs MonohybridMonohybrid

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

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

Questions...Questions...

What is the What is the phenotypephenotype??What is the What is the genotypegenotype??What is What is homozygoushomozygous??What is What is heterozygousheterozygous??What is What is monohybrid monohybrid

crossingcrossing??