Presentation on theme: "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."— Presentation transcript:
15-13Question of the DayIf 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.
2ReviewWhy 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)?
3Assignment5-12Read 12.2 and answer #s on the bottom of page 248 – DUE tomorrow (Friday 5-13)
4XA 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.XAXaXAXAXAXaXAYXAYXaY
5PedigreesPedigree – diagram that shows how a trait is inherited over several generationsSquares = ?Circles = ?
6XX 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?XrYXX
8Reading a Pedigree: Are there carriers? IF YES – it’s recessive IF NO – it’s dominant
9Reading a Pedigree:If it’s recessive, are there any male carrier? IF YES – it’s autosomalIF NO – it’s X-linked
10Reading a Pedigree:If it’s dominant, analyze an affected son.
11Question of the DayWhat type of disorder is shown in the pedigree below? How do you know? Use your notes from Friday!5-23Are there any carriers?Analyze an affected son (can a son get it from dad?)What type of disorder?
13Hemophilia (X-linked recessive) Pedigree from Queen Victoria What type of disorder?
14Announcement: Questish quizish type deal will be Friday 5-27
15X-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 recessiveExamples:Colorblindness – carried on X-chromosomeHemophilia – impaired blood clotting
16PedigreesCarriers – people who carry an allele for a disorder, but do not have the disorder (Heterozygous)Genetic disorders – any disease / disorder that has a genetic basisPolygenic – characteristics that are influenced by several genesExamples:Skin color – six genesOther examples – eye color, height, hair color
17PedigreesComplex characters - characteristics that are influenced strongly by both environment and genesSun = darker skinHeight = several genes but also nutrition and disease
18Multiple Alleles – genes that have three or more alleles (usually 2) Example: Blood TypeWhat are the blood types?ABOThree alleles – IA, IB, iBlood Types – A, B, AB, O
19ReviewWho 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?
20Question of the Day5-16An example of a human trait that is polygenic and a complex character = _____ because...
21Question of the DayHow do you identify a dominant genetic disorder on a pedigree (use notes page 5 if needed)?5-24
22Announcement: Questish quizish type deal will be Friday 5-27
23Antigens – proteins, carbs etc on outside of red blood cells Antibodies – immuno proteins that destroy unrecognized antigens
26Codominance – 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 traitsRed cow x white cow = roan cow
28Incomplete dominance – mix between two parents (blend) In incomplete dominance, you see a mix or blend of both traitsExample:straight hair mom X curly hair dad = wavy haired childRed flower x white flower = pink flower
30X-Linked Traits (review) Traits carried on the X chromosomeWho 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:ColorblindnessHemophilia
31X-linked DominantIf mother affected equal chance of sons / daughters affectedIf father affected All daughters will have, sons okNo carriers possible
32X-Linked RecessiveIf 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
33Autosomal DominantAffected individual 50 / 50 chance of producing affected childrenNo carriers possible
34Autosomal RecessiveOccurs if both parents are carriers (only 25% of the time)Carriers possible
36Single-Allele Traits – traits caused by one dominant allele Huntington’s Disease –caused by one dominant allele. Onset is so parents have children before they realize they have itForgetfulness, irritability, muscle spasms and mental illness, then deathGenetic testing now beginning to be used to determine if either parent has diseaseskipped sp11
37Pedigrees 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)