Genetics

Genetics Study of heredity Mendel and pea plants Fertilization- sperm and egg join Born in 1822 in what is now the Czech Republic Pea system

Hybrids- crosses between parents are true-breeding types Trait Ex. eye color, height Hybrids- crosses between parents are true-breeding types

Mendel figured out that characteristics aer determined by factors passed down generations

Gene- sequence of DNA that codes for a specific trait Ex. Eye color Allele- version of a gene Ex. blue eye color Diploid organisms have two alleles

Types of Alleles Dominant Recessive

Animation of Segregation Mendel’s Principle of Segregation: Two members of a gene pair segregate (separate) from each other during the formation of gametes. Animation of Segregation

Mendel’s Principle of Independent Assortment: Alleles for different traits assort independently of one another. Genes on different chromosomes behave independently in gamete production.

Diploid- 2 sets of chromosomes Haploid- 1 set of chromosomes -Gametes

Genotype Ex. BB Phenotype Ex. Brown eyes

Homozygous Heterozygous

Monohybrid cross

Probability and Genetics Probability- likelihood that an event will occur Multiplication rule “AND” Ex. What are the chances that you will have a boy and a boy? Addition rule “OR” Ex. What are the chances that you will have a boy or a girl?

2 Genes Law of segregation Alleles for the same gene must separate into different gametes (eggs and sperm) Ex. Bb Gamete 1: B Gamete 2: b

Law of Independent Assortment Genes for different traits can segregate independently during the formation of gametes

The laws and performing a dihybrid cross Dihybrid cross= 2 traits 16-square Punnett problem Steps: FOIL the possible gametes for both parents Create a 16-square Punnett box and place parent gametes Double-check you are doing it right by making sure all offspring have 4 letters, 2 of each kind!

Dihybrid Cross

Alternative Method Make a 4-square Punnett box for each individual trait and multiply the two results together Utilizing the multiplication rule!

Shape of Earlobe Recessive Dominant

Eye Color Dominant Recessive

Shape of Hairline Dominant Recessive

Tongue Roll Dominant Recessive

Tongue Fold Recessive Dominant

Shape of Little Finger Recessive Dominant

Hair on Middle Joint Recessive Dominant

Hair Color Recessive Dominant Red Hair – Any shade Any Other Color Hair

Hair Type Dominant Recessive

Eyelash Length Recessive Dominant

Number of Fingers Recessive Dominant

Cleft Chin Recessive Dominant

Dimples Dominant Recessive

Freckles Dominant Recessive

Hand Clasping Dominant Recessive 55% of People 45% of People