 HAPPY FRIDAY  A3 Bellwork: Computer Bellwork: Complete CoDominant Punnett Square in your bellwork page In rabbits, white coat color (CW) and black coat color (CB) are co-dominant; heterozygotes (CBCW) are spotted. Draw a Punnett Square that shows the phenotypes of the offspring from a heterozygous spotted rabbit and a homozygous white-coated rabbit? Small Group CHAMPS

50% Black with White Spots Shoulder Partner In rabbits, white coat color (CW) and black coat color (CB) are co-dominant; heterozygotes (CBCW) are spotted. Draw a Punnett Square that shows the phenotypes of the offspring from a heterozygous spotted rabbit and a homozygous white-coated rabbit? CB CW CB= Black CW = White CBCW = Black with White Spots Dad = CBCW Mom = CWCW CBCW CWCW CW CW 0% Black 50% Black with White Spots 50% White

Collect Today NOTHING! Assigned 6th and 7th Period - Final Exam Review Notecard (Day of Final) Genetics MAKE-UP Quiz (Monday) Page 77 – Family Tree Project Part 2 – Include Rubric and Punnett Squares (Monday) Genetics Exam (Monday) Genetics Vocabulary MAKEUP Quiz (WEDNESDAY) Biolo-Tree Extra Credit (Wednesday) Late Page 82 – Bikini Bottom Genetics (-50%) Page 85 – Incomplete Practice (-30%)

Finals Schedule Monday – Normal Day Tuesday – 7th Period Finals/No 6th Period Wednesday – 1st and 6th Period Finals/No 7th Period Thursday (1/2 Day) – 5th and 2nd Period Finals Friday (1/2 Day) – 3rd and 4th Period Finals

Genetics Review Mini-Quiz You need a piece of notebook paper, go to your lab station and answer the following questions. Only 2 people per piece of paper.

Genetics Review Mini-Quiz What is a genotype? A man is heterozygous for a trait. Will the dominant or recessive trait be expressed? Why? What does it mean if a woman is homozygous recessive? Using the letter “B,” write her genotype. What is a phenotype? Long eyelashes (E) are dominant to short eyelashes (e). A heterozygous woman is crossed with a homozygous dominant man. What is the percent chance their offspring will have short eyelashes? (Must draw a Punnett square) What does homozygous mean? Write an example. What does heterozygous mean? Write an example. What does it mean if a gene is expressed? What does a dihybrid cross show? What was Mendel’s predicted phenotypic ratio for a typical dihybrid cross? Hazel eyes (H) are dominant to green eyes (h). A homozygous dominant man is crossed with a homozygous recessive woman. What is the percent chance their offspring will have green eyes? (Must draw a Punnett square!) Turnip color is controlled by a gene that exhibits incomplete dominance; purebred red turnips (RR) crossed with purebred white turnips (WW) make purple turnips(RW). What are the chances of producing white offspring when you cross two purple parents? If a man with heterozygous type B blood (BO) marries a woman with type AB blood, what is the probability that they will have child with blood type B? When an orange lily (L) is crossed with a white lily (W) , a cream-colored lily (LW) will result. What is the probability of producing cream-colored lilies from two cream-colored parents? In humans, the gene for baldness (h) is recessive. This gene is located on the X chromosome but not on the Y chromosome. A man who is bald has a child with a woman who is heterozygous for baldness, but is not bald. What is the probability that….. A female child will be a carrier? A male child will be normal? A female child will develop the trait for baldness? A male child will develop the trait for baldness? Genetics Review Mini-Quiz

What are sex-linked traits and how are they modeled? Standard Essential Question What are sex-linked traits and how are they modeled? Standard B6F - Predict possible outcomes of genetic combinations such as Non-Mendelian Genetics. PG 83 Direct Instruction CHAMPS

Today we’re going to talk about a special case: sex-linked traits Remember: Each person inherits an X chromosome from mom and either an X or a Y from dad We use the letters X and Y to represent chromosomes (not alleles)

Sex-linked traits Are traits that are determined by either the Y or X chromosome If they are determined by the Y chromosome they are referred to as “Y-linked” Y-linked disorders are very rare and often cause infertility in men If they are determined by the X-chromosome they are referred to as “X-linked”

X-Linked Traits X-Linked Dominant: X-Linked Recessive: These conditions (such as vitamin D resistant rickets) are rare and can affect both men and women Men are more affected than women Both men and women can pass on the affected chromosome to their children These disorders (such as hemophilia and color blindness) more frequently affect men than women Both men and women can pass these traits on to their children (at different rates) An affected man/unaffected woman = sons who are unaffected, daughters who are carriers An affected woman/unaffected man = 50% chance of passing the trait. If she passes on her affected X chromosome, then her daughters will be carriers and her sons will be affected This is why men are more likely to be color blind than women

X-Linked Recessive (carrier mother)

XHX XHY XX XY X Y XH X H = hemophilia XX = FEMALE XY = MALE Mom =XHX Mrs. PigglyWiggly is a carrier of the sex-linked hemophilia allele, and Mr. PigglyWiggly is normal (as far as blood chemistry goes). Draw a Punnet square that shows the theoretical genotypes and phenotypes among their children. X Y H = hemophilia XX = FEMALE XY = MALE Mom =XHX Dad = XY XHX XHY XX XY XH X carrier female (XHX) 25%; normal female (XX) 25%; hemophilia male (XHY) 25%; normal male (XY) 25%

Practice Problems

Red-eyed females (XRXr) 50%; White-eyed males (XrY) 50% Table Group 1. In fruit flies (Drosophila), one eye color gene is x-linked, with a recessive white allele and a dominant red allele. If white-eyed female flies were bred to red-eyed male flies, what would be the expected offspring (assume all parental flies are purebred)? XR Y XR = Red Eyes Xr = White Eyes XX = FEMALE XY = MALE Mom =XrXr Dad = XRY XRXr XrY Xr Xr Red-eyed females (XRXr) 50%; White-eyed males (XrY) 50%

Female Carriers (XXC) 50%; Colorblind Males (XCY) 50% Shoulder Partner 2. Earl has normal color vision, while his wife Erma is colorblind. Colorblindness is an X-linked trait, and the normal allele is dominant over the colorblindness allele. If they have a large family, in what ways should the colorblindness affect their children? X Y XC = Colorblind X = Normal XX = FEMALE XY = MALE Mom =XCXC Dad = XY XXc XcY Xc Xc Female Carriers (XXC) 50%; Colorblind Males (XCY) 50%

Female Carriers (XXC) 50%; Independent 3. Ethan is colorblind. His wife, Edna, is homozygous for the normal color vision allele. If they have eight children, what percentage of them would you expect to be colorblind. Show a Punnett square and list genotypic and phenotypic ratios. XC Y XC = Colorblind X = Normal XX = FEMALE XY = MALE Mom =XX Dad = XCY XXc XY X X Female Carriers (XXC) 50%; Normal Males (XY) 50%

What is a genotype? The genes (letters) that determine a phenotype A man is heterozygous for a trait. Will the dominant or recessive trait be expressed? Why? Dominant because dominant covers recessive What does it mean if a woman is homozygous recessive? Using the letter “B,” write her genotype. Both of her genes are recessive (bb) What is a phenotype? The physical characteristics of an organism Long eyelashes (E) are dominant to short eyelashes (e). A heterozygous woman is crossed with a homozygous dominant man. What is the percent chance their offspring will have short eyelashes? (Must draw a Punnett square) 0% What does homozygous mean? Write an example. Homozygous means the same letters are present Ex. BB or bb What does heterozygous mean? Write an example. That the genes are different Ex. Bb What does it mean if a gene is expressed? The phenotype for that gene is seen (dominant) What does a dihybrid cross show? Genetic possibilities for 2 traits What was Mendel’s predicted phenotypic ratio for a typical dihybrid cross? 9:3:3:1 Hazel eyes (H) are dominant to green eyes (h). A homozygous dominant man is crossed with a homozygous recessive woman. What is the percent chance their offspring will have green eyes? (Must draw a Punnett square!) 0% Turnip color is controlled by a gene that exhibits incomplete dominance; purebred red turnips (RR) crossed with purebred white turnips (WW) make purple turnips(RW). What are the chances of producing white offspring when you cross two purple parents? 25% If a man with heterozygous type B blood (BO) marries a woman with type AB blood, what is the probability that they will have child with blood type B? 50% When an orange lily (L) is crossed with a white lily (W) , a cream-colored lily (LW) will result. What is the probability of producing cream- colored lilies from two cream-colored parents? 50% In humans, the gene for baldness (h) is recessive. This gene is located on the X chromosome but not on the Y chromosome. A man who is bald has a child with a woman who is heterozygous for baldness, but is not bald. What is the probability that….. A female child will be a carrier? 25% A male child will be normal? 25% A female child will develop the trait for baldness? 25% A male child will develop the trait for baldness? 25%