5-11-18 Understanding Inheritance Pedigrees

Do Now: Take out your homework Do Now: Take out your homework. Complete the following problems in your notebook. Compare and contrast a chromosome and a gene. Both contain genetic information. However, a chromosome contains the genetic information that controls many traits. A gene is a section of a chromosome containing genetic information for just one trait. The alleles that control how a trait is expressed are its . Genotype The actual expression of a trait is its . Phenotype A(n) is a model that is used to predict the possible genotypes and phenotypes of offspring. Punnett square A(n) shows the phenotypes of genetically related family members. Pedigree

Punnett Square Practice Problems Genotype = 0:2:2 (GG:Gg:gg) Phenotype = 2:2 (green peas:yellow peas) G g g Gg gg

Punnett Square Practice Problems 4. Genotype = 0:2:2 (RR:Rr:rr) Phenotype = 2:2 (red:white) R r r Rr rr

Punnett Square Practice Problems 7. Homozygous brown mouse = BB Heterozygous brown mouse = Bb Offspring Genotypes: BB = 50% Bb = 50% Offspring Phenotypes: Brown fur = 100% B B B b BB Bb

Punnett Square Practice Problems 8. Heterozygous white rabbit = Ww Offspring Genotypes: WW = 25% Ww = 50% ww = 25% Offspring Phenotypes: White fur = 75% Brown fur = 25% W w W w WW Ww ww

Punnett Square Practice Problems 9. Heterozygous red flowers = Rr Offspring Genotypes: RR = 25% Rr = 50% rr = 25% Offspring Phenotypes: Red flower = 75% White flower = 25% R r R r RR Rr rr

Punnett Square Practice Problems 10. Homozygous tall plant = TT Heterozygous tall plant = Tt Offspring Genotypes: TT = 50% Tt = 50% Offspring Phenotypes: Tall = 100% T T T t TT Tt

Punnett Square Practice Problems 11. Heterozygous white rabbit = Ww Homozygous black rabbit = ww Offspring Genotypes: Ww = 50% ww = 50% Offspring Phenotypes: White fur = 50% Black fur = 50% W w w Ww ww

Learning Objective: Students will be able to determine the genotypes and phenotypes of offspring and parents using pedigrees.

What does pedigree mean? X What does pedigree mean? Pedigree: a diagram that traces one trait through several generations of a family

Modeling Inheritance A pedigree shows phenotypes of genetically related family members. Pedigrees can help determine genotypes. Ex: 3 offspring have a trait – attached earlobes – that the parents do not have. Since the offspring received one allele from each parent, but neither parent displays the trait, the offspring must have received two recessive alleles.

= female = male

3 Example #1 2 How many girls? ___ How many boys? ___ mom dad daughter #1 daughter #2 son

The oldest offspring are placed on the left side of the pedigree and the youngest on the right side. mom dad oldest youngest daughter #1 daughter #2 son

A horizontal line connecting two shapes represents a cross/marriage. mom dad

Example #2 How many crosses/marriages? 2 A B C D E F G

A vertical line extending down from a marriage/cross represents that the couple has children. mom dad

? Example #3 4 How many couples have children? H A B G H C D E F J K L Q R S T

How do you show twins? A B C D E F

**A pedigree chart follows one trait. How do you show traits? Shading ( shaded = recessive ) RR Rr rr mutation **A pedigree chart follows one trait.

Pedigrees Practice: Stand Up, Hand Up, Pair Up Work on the first pedigree problem with one partner. When completed, stand up, hand up, and pair up with a different partner for the second problem.

Online Pedigree Activity http://www.zerobio.com/drag_gr11/pedigree/pedigree_overview.ht m When you arrive to the web page, click on “Tongue Rolling” at the top of the page.

Ex: Individual IV-1 and IV-3 are colored orange. Generations in a pedigree or identified with Roman numerals (I, II, III, IV, etc.) Individuals in pedigrees are identified by a Roman numeral and a number. Ex: Individual IV-1 and IV-3 are colored orange. If