Agenda

• Warmup-verbal• Chapter12PresentationProjects:PatternsofHeredityandHumanGenetics

• Chapter12Kahoot• Chapter12QuickQuizHomework:12.2SectionAssessment(pg322#1-5)

Chapter12:PatternsofHeredityandHumanGenetics

Pedigree

• Graphicrepresentationsofgeneticinheritance• Oftenusedtotracehowageneticdisorderispassedalong.

Table Talk Warm Up 1.  Isthetraitbeingstudied

dominantorrecessive?Howdoyouknow?

2.  AreII-1andII-2carriersofthetrait?Howdoyouknow?

3.  WhatistheprobabilitythatII-1andII-2willproduceanindividualwiththetraitbeingstudied?

4.  WhatisthelikelygenotypeofII-4forthetraitbeingstudied?

Genetic Disorders: Cystic Fibrosis • Recessivegeneticdisorder• MutationinCFTRgeneàmutatesproteinthatregulatestheflowofsaltandfluidsin/outofcells

• Causesthickmucusinlungs• Patientsneedphysicaltherapy,specialdietsandmedication

Tay-Sach’s Disease

• Recessivegeneticdisorder• Missinganenzymethatbreaksdownlipids(fats)incentralnervoussystem(brainandspine)àFatsaccumulate

• Muscleweaknessandsloweddevelopment• Causesdeathwithin4-5years

Phenylketonuria (PKU)

• Recessivegeneticdisorder• Missinganenzymethatconverts1aminoacid(Phe)toanotheraminoacid(Tyr)

• Phenylalaninebuildsupandleadstomentalimpairment

• Patientsmusteatalow-proteindiet(foodslowinPhe)

Huntington’s Disease

• Dominantgeneticdisorder-causedbyraredominantallele

• Nervecellsinthebrainbreakdownovertime• Causesuncontrolledmovements,emotionalproblems,andlossofcognition

Complex Patterns of Inheritance: Incomplete Dominance vs Codominance •  Incompletedominance:Dominantallelesmix/blend

•  Ex:Redflowerxwhiteflower=pinkflower

Codominance:Dominantallelesexpressedequally,butthereisnoblendingEx:Redflowerxwhiteflower=redandwhiteflowerEx:Heterozygousforsicklecellanemia

Sickle- Cell Anemia

•  Exampleofcodominance-Ifpersonhasonecopyofthesicklecellallele,halfoftheirredbloodcellswillbemisshapen

• Resultofsubstitutionmutationthatchanges1aminoacidduringtranslation

•  Slowedbloodflow,blockage,tissuedamage

•  Sex Chromosomes: 23rd pair of chromosomes that determine the sex (male or female) of a person. Sex-Linked Gene: A gene found only on a sex chromosome

Males:XYFemale:XX

Examples (X-Linked)

• Hemophilia:Blooddoesnotclotnormally

• Colorblindness

Group Discussion Time!

WhyareX-linkeddisordersmorecommoninmenthaninwomen?

Polygenic Inheritance

•  Inheritancepatternofatraitthatiscontrolledbytwoormoregenes.•  Eachgenestillhastwoalleles,buttherearemultiplegenesthat

determineatrait.Ex:eyecolor,height,skincolor

Multiple Alleles

•  Insteadofhavingtwoformsofanallele,therearemorethantwoforonegene

• Again,eachgenestillonlyhas2alleles,thereisjustmorethan2differentallelesthegenecanhave

•  Ex:haircolor,eyecolor,rabbitcoatcolor,bloodtype(A,B,O)

•  Antibodies-releasedbytheimmunesystemtofightantigens(foreignsubstances)

Abnormal Chromosome Number- Down Syndrome Trisomy:3copiesofachromosomeinsteadoftwoCanbeseenonakaryotype: