Block Day- April 25, 2012 Homework: none Make an entry- Entry 41:Heredity and Genetics2- 4/25/12 See attached entry

Symbols used for alleles The traditional symbols used for alleles are big and small letters The letter chosen usually refers to the dominant allele Example:R = Red allele r = Blue allele

The combination of alleles determines the observed characteristics RED allele Chromosome combination Allele combination Observed characteristic RED allele RED allele BLUE allele BLUE allele BLUE allele red, red red, blue (or blue, red) blue, blue RED BLUE

The combination of alleles determines the observed characteristics R Chromosome combination Allele combination Observed characteristic RR Rr rr RED BLUE RRrrr

The combination of alleles determines the observed characteristics R Chromosome combination GENOTYPE PHENOTYPE RR Rr rr RED BLUE RRrrr

Homozygous – the two alleles are the same RR and rr are homozygous genotypes Heterozygous – the two alleles are different Rr is a heterozygous genotype

Draw the enzymes and pigment molecules present in the cells of each type of flower below. GENOTYPE for flower type 2: Allele of chromosome 2A= Y1 (functional enzyme ) PHENOTYPE of flower type 2 : nucleus Y1 Y2 Yes or no, is any functional enzyme Y in the cell? Allele of chromosome 2B= Y2 (non-functional enzyme ) 2A 2B 1B 1A YES RED WHAT DOES Rr ACTUALLY MEAN? Rr

Possible combinations of inherited chromosomes/genes R r DadMom R r Parents Possible Offspring r r R R r R X Order doesn’t matter, these two are the same (Rr) What are all possible genotypes produced from the parents? RR, Rr, rr

Punnett squares organize all possible offspring combinations R r X Rr R r RR Rrrr Rr DadMom

1 out of 4 possibilities is rr = What is probability of Rr? How many out of 4 are red? What is the probability of red? What is the probability of blue? Rr RRRRr r rr Genotypic ratio= 1RR: 2Rr:1rr 25 % 50 % 3/4 75 % 25 % R= red flower allele r= blue flower allele Phenotypic ratio=3 Red:1 blue

Your turn: What are all possible genotypes and phenotypes produced by crossing Rr with rr? Complete the Punnett Square rr RRr rrr

Punnett squares predict ratios of all genotypes and phenotypes produced Genotypic ratio = 2 Rr:2 rr or 1Rr : 1 rr Phenotypic ratio = 2 Red:2 Blue or 1 Red : 1 Blue rr RRr rrr R= red flower allele r= blue flower allele

Punnett square practice Calculate the predicted genotypic and phenotypic ratios 1)Hh X HH H(hairy) is dominant over h(not hairy) 2a) Gg X gg G(green sepals) is dominant over g(yellow sepals) 2b) What would the cells of the green and yellow plants look like? (functional vs non-functional)

Genotypic ratio = 2 HH:2 Hh or 1HH : 1Hh Phenotypic ratio = 4 Hairy: 0 Non-hairy HH HHH hHh

Genotypic ratio = 2 Gg:2 gg or 1Gg : 1gg Phenotypic ratio = 2 Green: 2 Yellow or 1 Green : 1 Yellow gg GGg ggg

GENOTYPE for Green Flower (Gg) : Allele of chromosome A= C1 (functional enzyme ) PHENOTYPE of flower type 2 : nucleus Yes or no, is any functional enzyme C in the cell? Allele of chromosome B= C2 (non-functional enzyme ) Y1 Y2 A B 1B 1A GENOTYPE for yellow flower (gg): Allele of chromosome A= C2 (non-functional enzyme) PHENOTYPE of flower type 3 : nucleus Y2 Yes or no, is any functional enzyme Y in the cell? Allele of chromosome B= C2 (non-functional enzyme ) A B 1B 1A YES Green NO Yellow

Make an entry- Entry 42: Punnett Square Worksheet- 4/25/12 See attached entry

#1 In rabbits, black fur is dominant over white fur. Show the cross of a heterozygous black male with a homozygous white female. Parents: Bb x bb b b Genotypic Ratio: B 1 Bb : 1bb Phenotypic Ratio: b 1 black: 1 white Bb bb

#2 Tall is dominant over short in pea plants. Show the cross of a homozygous short plant is crossed with a homozygous tall plant. Parents: tt x TT Genotypic Ratio: 4 Tt (or 100% Tt) Phenotypic Ratio: All or 100% Tall Tt T t

# 3 In humans, free-ear lobes are dominant to attached ear lobes. Two parents that are both heterozygous free are expecting a child. What are the chances that the child will have free ear lobes of attached? Parents: Ff x Ff F f Genotypic Ratio: F 1 FF:2Ff: 1ff Phenotypic Ratio: f 3 Free: 1 attached FF Ff ff

#4 S=smooth s= wrinkled Parents: ss x Ss Genotypic ratio: 2 Ss:2 ss Phenotypic ratio: 2 smooth: 2 wrinkled

#5 S=smooth s= wrinkled Parents: Ss x Ss Genotypic ratio: 1 SS: 2Ss: 1ss Phenotypic ratio: 3 smooth: 1 wrinkled

#6 B=blue eyes b=red eyes Parents: Bb x bb Genotypic ratio: 2 Bb: 2 bb Phenotypic ratio: 2 blue eyes: 2 red eyes

#7 R= red eyes r= white eyes Parents: rr x rr Genotypic Ratio: 4 rr or all rr Phenotypic: 4 white eyes or all white eyes

#8 A homozygous dominant brown mouse is crossed with a heterozygous brown mouse (tan is the recessive color). Parents: BB x Bb B b Genotypic Ratio: B 1 BB : 1Bb Phenotypic Ratio: B All Brown or 4 Brown: 0 Tan BB Bb BBBb

#9 Two heterozygous white (brown fur is recessive) rabbits are crossed. Parents: Ww x Ww Genotypic Ratio: 1WW:2Ww:1ww Phenotypic Ratio: 3 WHITE: 1 BROWN W w W w WW Ww ww