Punnett Square Genetics Intro. Trait: genetically determined feature of an organism Gene: a section of a chromosome that codes for a trait; you have 2 alleles for every gene Allele: alternate forms of a gene that are shown with letters; you received one allele from each parent

Punnett Square Genetics Intro. Dominant: the allele that will be expressed even if a recessive one is present Recessive: these alleles are hidden when dominant ones are present; the only way recessives will be expressed is if there are two of them for the gene

Punnett Square Genetics Intro. Genotype: the allele combination possessed; it is written out in letters Phenotype: the features determined by the genes; it is written out in words

Part 1 – Simple Crosses #1 Rr R R RRRr RRRr Genotype ratio 2/4 RR : 2/4 Rr Phenotype ratio 4/4 Round

Part 1 – Simple Crosses #2 Gg G G GGGg GGGg Genotype ratio 2/4 GG : 2/4 Gg Phenotype ratio 4/4 Green

Part 1 – Simple Crosses #3 Tt T t TTTt tt Genotype ratio 1/4 TT : 2/4 Tt : 1/4 tt Phenotype ratio 3/4 tall : 1/4 short

Part 1 – Simple Crosses #4 rr R r Rr rr Genotype ratio 2/4 Rr : 2/4 rr Phenotype ratio 2/4 Round : 2/4 wrinkled

Part 1 – Simple Crosses #5 Gg G g GGGg Gggg Genotype ratio 1/4 GG : 2/4 Gg : 1/4 gg Phenotype ratio 3/4 green : 1/4 yellow

Part 1 – Simple Crosses #6 GG g g Gg Genotype ratio 4/4 Gg Phenotype ratio 4/4 Green

Part 1 – Simple Crosses #7 TT t t Tt Genotype ratio 4/4 Tt Phenotype ratio 4/4 tall

Part 1 – Simple Crosses #8 bb B b BbBb bbbb Genotype ratio 2/4 Bb : 2/4 bb Phenotype ratio 2/4 brown : 2/4 white

Part 2 - Pedigree Charts #1 Does the trait show up more often in males or females or does it affect males and females [somewhat] equally? Males Are there carriers? Yes Therefore it is: Sex-linked recessive

Part 2 - Pedigree Charts #2 Does the trait show up more often in males or females or does it affect males and females [somewhat] equally? Equal Are there carriers? No Therefore it is: Autosomal dominant

Part 2 - Pedigree Charts #3 Does the trait show up more often in males or females or does it affect males and females [somewhat] equally? Females Are there carriers? No Therefore it is: Sex-linked dominant

Part 2 - Pedigree Charts #4 Does the trait show up more often in males or females or does it affect males and females [somewhat] equally? Equal Are there carriers? Yes Therefore it is: Autosomal recessive

Part 3 – Special Punnett Squares #1 IAIA IBIB i IAIA IBIB i I A I A = 1/9 I B I B = 1/9 ii = 1/9 I A i = 2/9 I B i = 2/9 I A I B = 2/9 Type A= 3/9 Type B= 3/9 Type AB= 2/9 “Universal Recipient” Type O= 1/9 “Universal Donor” IAIAIAIA IAIBIAIB IAiIAi IAIBIAIB IBIBIBIB IBiIBi IAiIAi IBiIBi ii

Part 3 – Special Punnett Squares #2 RR r r Rr Genotype ratio 4/4 Rr Phenotype ratio 4/4 pink

Part 3 – Special Punnett Squares #3 Rr R r RRRr Rrrr Genotype ratio 1/4 RR : 2/4 Rr : 1/4 rr Phenotype ratio 1/4 red : 2/4 pink : 1/4 white

Part 3 – Special Punnett Squares #4 rr R r RrRr rrrr Genotype ratio 2/4 Rr : 2/4 rr Phenotype ratio 2/4 pink : 2/4 white

Part 3 – Special Punnett Squares #5 XhXh Y XHXH XhXh H = normal; h = hemophilia XHXhXHXh XhXhXhXh XHYXHY XhYXhY 1/4 X H X h = carrier female 1/4 X h X h = hemophiliac female 1/4 X H Y = normal male 1/4 X h Y = hemophiliac male

Part 3 – Special Punnett Squares #6 XcXc Y XCXC XCXC C = normal; c = color-blind XCXcXCXc XCXcXCXc XCYXCY XCYXCY 2/4 X C X c = carrier female 2/4 X C Y = normal male

Enrichment Sample Problem #1 Step 1 Determine the genotypes of the parents. Step 2 Determine the gamete genotypes produced by each parent. Step 3 Set up a Punnett square using the gamete genotypes. Step 4 Combine the gamete genotypes from one parent with those from the other parent to show all possible offspring genotypes. Step 5 State the genotype ratio and the phenotype ratio. RT RRTT

Step 1 Determine the genotypes of the parents. Step 2 Determine the gamete genotypes produced by each parent. Step 3 Set up a Punnett square using the gamete genotypes. Step 4 Combine the gamete genotypes from one parent with those from the other parent to show all possible offspring genotypes. Step 5 State the genotype ratio and the phenotype ratio. rT RT Rt RRTt RrTt RRTt RrTt RRTt RrTt RRTt RrTt Enrichment Sample Problem #2

Step 1 Determine the genotypes of the parents. Step 2 Determine the gamete genotypes produced by each parent. Step 3 Set up a Punnett square using the gamete genotypes. Step 4 Combine the gamete genotypes from one parent with those from the other parent to show all possible offspring genotypes. Step 5 State the genotype ratio and the phenotype ratio. gtgTGtGT Gt gT gt GGTTGGTtGgTTGgTt GGTtGGttGgTtGgtt GgTTGgTtggTTggTt GgTtGgttggTtggtt Enrichment Sample Problem #3

Enrichment Practice #1 rbrBRbRB RRBBRRBbRrBBRrBb RRBBRRBbRrBBRrBb RRBBRRBbRrBBRrBb RRBBRRBbRrBBRrBb A. RrBb x RRBB C. 16/16 running, black mice

Enrichment Practice #2 RB Rb rb RRBb RrBb A. RRBB x Rrbb C. 16/16 running, black mice

Enrichment Practice #3 rb rrbb A. rrbb x rrbb C. 16/16 waltzing, brown mice

Enrichment Practice #4 RbRBRbRB rb RrBbRrbb RrBbRrbb RrBbRrbbRrBbRrbb RrBbRrbbRrBbRrbb RrBbRrbbRrBbRrbb A. RRBb x rrbb C. 8/16 running, black mice : 8/16 running, brown mice

B = blue b = yellow T = tail t = no tail Heterozygous blue, homozygous tail X Yellow, heterozygous tail What are the parent genotypes? BbTT X bbTt What are the possible gamete genotypes? BT, BT, bT, bT, bT, bt, bT, bt

bT BT bT bt bT bt bbTt bbTT bbTt bbTT bbTt bbTT BbTt BbTT BbTt BbTT BbTt BbTT BbTt BbTT