Section 11-3 Exploring Mendelian Genetics

Wanted To Know If: Segregation Was Truly Independent or Does The Segregation Of One Pair Of Alleles Affect The Segregation Of Another Pair Of Alleles????

Mendel Performed A Two Factor Cross  He Crossed Round/Yellow RRYY  With Wrinkled/Green rryy This Provided The F 1 Hybrids That He Needed.

To make a Punnet square of a cross with two traits first figure out the possible gametes. RRYY All gametes would be RY rryy All gametes would be ry

All Hybrids would be RrYy

9 : 3 : 3 : 1 Expected ratio for independent assortment phenotypes.

556 Seeds Produced 315 Round/Yellow F 1 Parental Phenotypes 32 Wrinkled/Green Plus 209 Unique Phenotypes Can Only Form Via 9:3:3:1Independent Assortment

The Alleles For Seed Shape And Color Segregated Independently INDEPENDENT ASSORTMENT did occur. Therefore These Alleles DO NOT Influence Each Others Inheritance

The Principle Of Independent Assortment States That Genes For Different Traits Can Segregate Independently During The Formation Of Gametes.

1. Inheritance of Biological Characteristics Is Determined By Individual Units Known As Genes. In Organisms That Reproduce Sexually, Genes Are Passed From Parents To Their Offspring.

2. Where Two or More Forms Of The Alleles Exist, Some Forms Of The Allele Many Be Dominant And Others May Be Recessive.

3. In Most Sexually Reproducing Organisms, Each Adult Has Two Alleles In Each Gene – One From Each Parent 4. These Alleles Are Segregated From Each Other When Gametes Are Formed.

5. Alleles Contained In Different Genes Usually Segregate Independently Of One Another

Key Concept: Some Alleles Are Neither Dominant Nor Recessive, And Many Traits Are Controlled By Multiple Alleles or Genes.

Red Flower Crossed With White Flower Results In Pink Flower. In Incomplete Dominance The Heterozygous Phenotype Is Between The Homozygous Phenotypes. ( Both Alleles Expressed In One Cell)

 Both Alleles Completely Expressed Red Hair Cattle Crossed With White Haired Cattle Produce Roan (Pink Brown) Cattle That Have Both Colored Hairs. (Both Alleles Expressed Independently)

REDWHITE ROAN

 A Gene Is Controlled By >2 Alleles.  Individuals Can Only Have 2 Alleles  Populations Can Have More Than Two  Rabbit Fur Color  Blood Types  Eye Color

 Phenotypes Produced By The Interaction Of Several Genes.  Human Skin Color Is Controlled By More Than 4 Different Genes.  Eye Color is Controlled By At Least 3 Genes