genetics part 2
DESCRIPTION
TRANSCRIPT
Inheritance
Mendel – Found that alleles show up in predictable patterns and that some alleles show up more often than others•Homozygous (Pure-Breeds) - both alleles are the same (PP or pp)
•Heterozygous (Hybrids) - both alleles are different (Pp)
•Carriers – heterozygotes for a recessive trait
HomozygousPure-Breed Crosses result in: 100% chance dominant phenotype
Heterozygous
Hybrid Crosses result in: 75% chance dominant phenotype25% chance recessive phenotype
Compare
What makes the difference between a 100% chance of the dominant phenotype and only 17% chance of the dominant phenotype ?
Pure-Breed Crosses result in: 100% chance dominant phenotype
Hybrid Crosses result in: 75% chance dominant phenotype25% chance recessive phenotype
Generations
First Generation: First Filial (F1)
Second Generation: Second Filial (F2)
Third Generation: Third Filial (F3)
Parents: P1 generation
Chance of Inheritance
100% chance 75% chance 75% chance 0% chance
First Generation: First Filial (F1)100% chance dominant phenotype
Second Generation: Second Filial (F2)75% chance dominant phenotype
Third Generation: Third Filial (F3)63% chance dominant phenotype
Parents: P1 generation
Alleles can be tracked through multiple generations and probabilities determined
Inheritance
Alleles can be tracked through multiple generations and probabilities determined
First Generation: First Filial (F1)100% chance dominant phenotype
Second Generation: Second Filial (F2)75% chance dominant phenotype
Third Generation: Third Filial (F3)63% chance dominant phenotype
100% chance 75% chance 75% chance 0% chance
Parents: P1 generation
Practice
• Video on making punnett squares• In your notebook complete the Probability
(Long vs Short Big Toe) Lab.
Linked genes (genes that occur very close to one another on a chromosome) are the exception
Write these 4 ideas from Mendel in your notebook
Summary of Mendel’s Principles
Gregor Mendel’s work forms the basis of modern genetics:• Genes are passed from parent to offspring
• Some forms of genes (alleles) are dominant while others are recessive
• Genes randomly segregate (independent assortment) when gametes are formed
• The alleles for different genes usually segregate independently of one another
DNA Chromosomes• From Chromosome to DNA• How DNA is packaged animation• Meiosis is how DNA is copied and
sepereted to make gametes (sperm and egg)• Complete cornell notes for the
Meiosis video and glue onto page ___ of your notebook– What is the purpose of Meiosis and Mitosis?
• Complete the lab “Why don’t we look like our siblings” and glue in your notebook
Solving Punnett SquaresIf a round pea plant (AA) is crossed with a wrinkled pea plant (aa), what percent of the offspring will be:• Round?• Wrinkled?
If two heterozygous round pea plants are crossed, what percent of the offspring will be:• Round?• Wrinkled?
If a heterozygous round pea plant is crossed with a homozygous wrinkled pea plant, what percent of the offspring will be:• Round?• Wrinkled?
Solve these in your notebook.