7.1 Chromosomes and Phenotype: Autosomal Genetic Disorders Set up Cornell Notes on pg. 77 Topic: 7.1 Chromosomes and Phenotype: Autosomal Genetic Disorders Essential Questions: Why is it impossible to have a “carrier” of an autosomal dominant disorder? 7.1 Chromosomes and Phenotype: Autosomal Genetic Disorders 2.1 Atoms, Ions, and Molecules Why is it impossible to have a “carrier” of an autosomal dominant disorder? KEY CONCEPT The chromosomes on which genes are located can affect the expression of traits.

KEY CONCEPT The chromosomes on which genes are located can affect the expression of traits.

Many human genetic disorders are caused by autosomal genes, and can be predicted the same as flower color, or Pea shape Autosomal genetic disorders: disorders that have no relation to the sex of an individual Can be male or female in equal porportions Ex: Albinism

Autosomal recessive disorder: Any offspring with two recessive genes (cc) will have the disease/disorder C c CC Cc Ex: Cystic Fibrosis C c Cc cc Disorder

A carrier is heterozygous (Cc) for a recessive disorder and does not show any signs or symptoms, but can pass on the disorder to their offspring C c CC Cc Ex: Cystic Fibrosis C *carrier c Cc cc *carrier Disorder

Video: Autosomal Recessive Disorders (4m52s) Pg. 76 Take at least 10 bullets

Albinism is a autosomal recessive disorder characterized by a lack of pigment in skin, hair, and eyes.

A a A a A a Genotype: Genotype: Phenotype: Phenotype: Carriers?: mom mom A a A a dad dad A a Genotype: Phenotype: Carriers?: Are either of the parents albino? Genotype: Phenotype: Carriers?: Are either of the parents albino? Fill out these punnett sqs. What is the probability that the offspring will have albinism?

A a A a A a AA Aa *carrier Aa *carrier aa *disorder AA Aa *carrier Aa Genotype: AA, Aa Phenotype: O% albino 100% non-albino Carrier?: 50% carrier Parents?: Neither parent is albino Genotype: Aa Phenotype: 50% albino 50% non-albino Carrier?: 50% carrier Parents: Father is albino

Both Mom and Dad have to either have the disorder or be carriers for offspring to be affected with an autosomal recessive disorder!

Video: ABC’s Special Report: Albinism- Caught between light and dark (6m54s)

Autosomal DOMINANT Disorders: any offspring with a dominant allele will have the disorder Dominant disorders are uncommon No carriers! ( Hh- would show the trait) H h Hh hh h *anywhere there is an H the child will have the disease Disorder Hh hh h Disorder

Treacher Collins Syndrome is an autosomal Dominant disorder. It can lead to the person having no cheekbones (so the eyes droop), and they may also have a cleft palate and under developed ears.

T t t Tt *disorder tt Tt *disorder tt Genotype: Phenotype: If Mom or Dad have the disorder 50/50 chance the offspring will also have the disorder. Genotype: Tt, tt Phenotype: 50% will have TCS 50% non-TCS

Video: Ashley’s Story- Treacher Collins Syndrome (5m11s)

7.1 Chromosomes and Phenotype: Sex-linked Genes Set up Cornell Notes on pg. 79 Topic: 7.1 Chromosomes and Phenotype: Sex-linked Genes Essential Questions: 1. Describe how Sex-linked genes are expressed differently in men than women. 7.1 Chromosomes and Phenotype: Sex-linked Genes 2.1 Atoms, Ions, and Molecules 1. Describe how Sex-linked genes are expressed differently in men than women.

Genes on sex chromosomes are called sex-linked genes. Y chromosome genes in mammals are responsible for male characteristics. X chromosome genes in mammals affect many traits.

Sex chromosomes: determine gender Gene expression is often related to whether a gene is located on an autosome or a sex chromosome Sex chromosomes: determine gender Autosomes: all other chromosomes- no relation to gender All genes that Mendel studied were autosomes Most traits are the result of autosomal genes

Because the X and Y chromosomes have different genes, sex-linked genes have a pattern of expression that is different from autosomal genes

Only 1 Y, and 1 X because Males have no second copies of sex-linked genes ALL of a male’s sex-linked genes are expressed So even if all the sex-linked genes of a male are recessive, they will be expressed

Female mammals have an XX genotype. Expression of sex-linked genes is similar to autosomal genes in females. X chromosome inactivation randomly “turns off” one X chromosome ensures that females, like males, have one functional copy of the X chromosome in each body cell

X Chromosome inactivation example: Tortoiseshell and Calico Cats (always female) The female cats have white fur; and black (b) or orange fur (B) alleles on their X Chromosomes- these will be expressed randomly Males have white fur; and one sex-linked gene for either black (b) or orange (B) fur X

X b X b B b X X X-chromosome inactivation X B Black Y

X b X b B b X X X-chromosome inactivation X B Orange Y

X b X b B b B X X X X b X B b X Y b X Y Y

Males only have one X chromosome so one color will be present (recessive OR dominant) Female cats have two X chromosomes. Each patch of fur can be different depending on which X chromosome “turns off”

X B X b B b b b X X X X X b Calico Black B X Y b X Y Y

What are the chances of getting a black cat? 50% black cats Answer the questions about your cat cross: What are the chances of getting a black cat? 50% black cats What are the chances of getting an orange, male cat? 25% orange male cat What are the chances of a male cat being orange? 50% male orange cat What are the chances of a female being calico? 50% female calico

Color blindness is a recessive sex-linked trait. A normal man marries a woman who is a carrier for color blindness. Predict the heredity of their offspring. (Use “b” to show color blindness) Phenotypes: Male- ______% colorblind ______% Non-colorblind ______% Carrier Female-

Color blindness is a recessive sex-linked trait. A normal man marries a woman who is a carrier for color blindness. Predict the heredity of their offspring. (Use “b” to show color blindness) Phenotypes: Male- 50% Colorblind 50% Non-CB NO CARRIERS Female- 0% Colorblind 50% carrier X B X b b B B B B X X X X X B X Y b Y X Y

A white-eyed male fly mates with a red eyed female fly to produce: 24 white-eyed males, 27 white-eyed females, 26 red-eyed males, and 23 red-eyed females. Can this trait be sex-linked? Prove your answer by completing 2 test crosses. (r=white eyes) Phenotypes: Male- ____% Red eyes ____%White eyes Female-

A white-eyed male fly mates with a red eyed female fly to produce: 24 white-eyed males, 27 white-eyed females, 26 red-eyed males, and 23 red-eyed females. Can this trait be sex-linked? Prove your answer by completing 2 test crosses. (r=white eyes) White eyes is a recessive sex-linked trait. X R X R Phenotypes: Male- 100% Red eyes 0% White eyes Female- 100% Red Eyes R r R r r X X X X X R X Y R Y X Y

X X X X X X X X Y Y X Y White eyes is a recessive sex-linked trait. A white-eyed male mates with a red eyed female to produce: 24 white-eyed males, 27 white-eyed females, 26 red-eyed males, and 23 red-eyed females. Can this trait be sex-linked? Prove your answer by completing 1-2 test crosses. (r=white eyes) X R X r Phenotypes: Male- 50% Red eyes 50% White eyes Female- 50% Red Eyes R r r r r X X X X X R X Y r Y X Y