2 Do Now1. How do you describe this genotype: RR? (homozygous recessive, heterozygous, etc.)2. If having hair in your ears is a dominant trait, and you have the gene combination Hh, will you have hair in your ears?3. What do you call the physical appearance that an organism shows due to it’s gene combination (the way an organism looks)?
3 GOAL To use punnett squares to predict the traits of offspring To become familiar with pedigree charts
4 ReviewBrown eyes is dominant. Blue eyes is recessive. The mother is heterozygous and the father is heterozygous.What percentages of blue-eyed and brown eyed offspring will they get?
5 Bb x Bb B= Brown b=Blue B b BB Bb B Bb bb b Genotypes: 25% Homozygous Dominant BB50 % Heterozygous Bb25% Homozygous Recessive bbBbBB BbBBb bbbPhenotypes75% Brown Eyed25% Blue Eyed
6 ReviewHaving a short middle toe is a dominant trait. Having a long middle toe is recessive. If a heterozygous male and a homozygous recessive female have a child- what is the probability that the offspring will have a long middle toe?
7 Mm x mm M m Mm mm m Mm mm m M= Short Middle Toe m= Long Middle Toe Genotypes:50 % Heterozygous Mm50% Homozygous Recessive mmMm mmmMm mmmPhenotypes50% Short middle toe50% Long middle toe
8 Create a punnett square: A couple would like to have children- however, the husband has cystic fibrosis. Having cystic fibrosis is a recessive trait. The wife, however, does not have cystic fibrosis- but she is a carrier for the disease (she is heterozgyous). What are their chances for having a child with cystic fibrosis?
9 Bb x bb B= Normal b=Cystic Fibrosis B b Bb bb b Bb bb b Genotypes: 50 % Heterozygous Bb50% Homozygous recessive bbBb bbbBb bbbPhenotypes50% Carrier-Healthy50% cystic fibrosis
10 More Genetics Terms Carrier When an individual is heterozygous (carries the disease gene), although they don’t actually have the disease (Cc).
11 More Genetics Terms Pure Bred Homozygous recessive (bb) and Homozygous dominant (BB)AKA True breeders
12 More Genetics TermsHybridHeterozygous individuals
13 More Genetics TermsSex ChromosomesOut of your 46 chromosomes - 2 of them are sex chromosomesMale = XYFemale = XX
14 Punnett Example: XX x XY Genotypes:50 % XX50% XYXX XXXXY XYYPhenotypes50% Boy50% GirlX= Female Y=Male
27 Genetics Assessment --> Complete the Punnett Square Word Problems --> Genetics Lab- Look at characteristics of classmates--> Worksheet: “Should this Dog be Called Spot?”Practicing Punnett Squares on the Internet
28 DO NOW Get out your homework Go over your answers with your SEAT PARTNERIf you aren’t done, FINISH IT!!We will go over the answers together in a few minutes