5-13 Question of the Day If a man has an X-linked recessive disorder and his mate does not carry the allele for it, _____ of their girls will be carriers. _____ of their boys will inherit the harmful allele. 

Review Why are there more X sex linked traits? Linked genes are usually … Mutations in an organisms gametes = ? Mutations that cause death = ? Example from class = ? What type of mutation causes Down syndrome (2 correct answers)?

Assignment 5-12 Read 12.2 and answer #s 1-8 on the bottom of page 248 – DUE tomorrow (Friday 5-13)

XA Xa XA Y Question of the Day 5-20 A female carrier of an X-linked recessive allele for a disorder hooks up with a normal male, their sons have a _____ chance of inheriting the disorder. _____ of their daughters will have it, but _____ of them are likely to be carriers. XA Xa XA XAXA XaXA Y XAY XaY

Pedigrees Pedigree – diagram that shows how a trait is inherited over several generations Squares = ? Circles = ?

XX XrY Study the simple pedigree. The man is red (pink) because…? The daughters are blue because …? Is it possible to get a son that has Hemophilia or is a carrier? Explain! If one of the sons hooks up with a female carrier, what will happen? XrY XX

Pedigrees Standard Key:

Reading a Pedigree: Are there carriers? IF YES – it’s recessive IF NO – it’s dominant

Reading a Pedigree: If it’s recessive, are there any male carrier? IF YES – it’s autosomal IF NO – it’s X-linked

Reading a Pedigree: If it’s dominant, analyze an affected son.

Question of the Day What type of disorder is shown in the pedigree below? How do you know? Use your notes from Friday! 5-23 Are there any carriers? Analyze an affected son (can a son get it from dad?) What type of disorder?

Review 5-20 What type of disorder?

Hemophilia (X-linked recessive) Pedigree from Queen Victoria What type of disorder?

Announcement: Questish quizish type deal will be Friday 5-27

X-Linked Traits Traits carried on the X chromosome Who will show more X-linked disorders, males or females? Why? Males – b/c they only have one X (XY) so it doesn’t matter if trait is dominant or recessive Examples: Colorblindness – carried on X-chromosome Hemophilia – impaired blood clotting

Pedigrees Carriers – people who carry an allele for a disorder, but do not have the disorder (Heterozygous) Genetic disorders – any disease / disorder that has a genetic basis Polygenic – characteristics that are influenced by several genes Examples: Skin color – six genes Other examples – eye color, height, hair color

Pedigrees Complex characters - characteristics that are influenced strongly by both environment and genes Sun = darker skin Height = several genes but also nutrition and disease

Multiple Alleles – genes that have three or more alleles (usually 2) Example: Blood Type What are the blood types? ABO Three alleles – IA, IB, i Blood Types – A, B, AB, O

Review Who will show more X-linked disorders, males or females? Why? Linked genes are usually … Germ-cell mutations = ? Chromosomal mutations cause changes to chromosome ___ or ___. Example from class = ? What is a pedigree?

Question of the Day 5-16 An example of a human trait that is polygenic and a complex character = _____ because...

Question of the Day How do you identify a dominant genetic disorder on a pedigree (use notes page 5 if needed)? 5-24

Announcement: Questish quizish type deal will be Friday 5-27

Antigens – proteins, carbs etc on outside of red blood cells Antibodies – immuno proteins that destroy unrecognized antigens

http://nobelprize.org/educational_games/medicine/landsteiner/ “Blood typing activity” google – first link

Universal donor

Codominance – when both alleles are expressed in the phenotype (IA, IB – neither is dominant over the other – both carbs are produced on cell surface) In codominance, you see both traits Red cow x white cow = roan cow

Codominance

Incomplete dominance – mix between two parents (blend) In incomplete dominance, you see a mix or blend of both traits Example: straight hair mom X curly hair dad = wavy haired child Red flower x white flower = pink flower

Incomplete Dominance

X-Linked Traits (review) Traits carried on the X chromosome Who will show more X-linked disorders, males or females? Why? Males – b/c they only have one X (XY) (doesn’t matter if trait is dominant or recessive) Examples: Colorblindness Hemophilia

X-linked Dominant If mother affected  equal chance of sons / daughters affected If father affected  All daughters will have, sons ok No carriers possible

X-Linked Recessive If mother carrier  50% chance son will be affected, no daughters will have (females can be carriers) If father affected  Sons will be ok, All daughters are carriers

Autosomal Dominant Affected individual  50 / 50 chance of producing affected children No carriers possible

Autosomal Recessive Occurs if both parents are carriers (only 25% of the time) Carriers possible

Handout

Single-Allele Traits – traits caused by one dominant allele Huntington’s Disease – caused by one dominant allele. Onset is 30-40 so parents have children before they realize they have it Forgetfulness, irritability, muscle spasms and mental illness, then death Genetic testing now beginning to be used to determine if either parent has disease skipped sp11

Pedigrees Standard Key: = normal male or = carrier male (one bad allele + one good allele) = affected male (has disease / disorder) = normal female = carrier female (one bad allele + one good allele) = affected female (has disease / disorder)