Chapter 11 Complex Inheritance Patterns and Human Genetics

Chapter 11: Complex Inheritance Patterns and Human Genetics Section 1: Basic Patterns of Human Inheritance

Genetic Disorders Caused by Single Allele Dominant – Huntington’s disease – Polydactyly – Achondroplasia Recessive – Albinism – Cystic fibrosis – Phenylketonuria – Tay-Sachs

Pedigree. Huntington Disease To return to the chapter summary click escape or close this document.

Symbols Used by Geneticists To return to the chapter summary click escape or close this document.

Fictional Pedigree To return to the chapter summary click escape or close this document.

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Chapter 11: Complex Inheritance Patterns and Human Genetics Section 2: Complex Patterns of Inheritance

Complex Patterns of Inheritance Incomplete Dominance – 3 phenotypes – Intermediate form – Example Red flower x white flower = ? Codominance – 3 phenotypes – Both traits expressed individually in third phenotype – Example: White chicken x black chicken = ?

Incomplete Dominance To return to the chapter summary click escape or close this document.

Codominance Sickle Cell Disease – Homozygous sickle cell disorder – Change in hemoglobin – protein in RBC’s that carry oxygen/carbon dioxide – Heterozygous: – Heterozygous individuals have advantage

Multiple Alleles – More than 2 possible alleles – Number of phenotypes equals number of different alleles Example: – Blood type – Coat color in rabbits

Multiple Alleles Blood types Three alleles – IA = A type – IB = B type – I = O type – Also shows codominance

ABO Blood Group. Surface Pro A To return to the chapter summary click escape or close this document.

ABO Blood Group. Surface Pro B To return to the chapter summary click escape or close this document.

ABO Blood Group. Surface Pro B-B To return to the chapter summary click escape or close this document.

ABO Blood Group. No Surface To return to the chapter summary click escape or close this document.

Blood Types Type Alleles Antigens Antibodies A B AB O Accepts Donates to:

Blood Types Type Alleles Antigens Antibodies A I AI A, I Ai A B Accept Donates s to: A, O A, AB B I BI B, I Bi B A B, O AB I AI B A and B None O ii None A, B, AB, O A and B O B, AB AB A, B, AB, O

Blood types IA and IB are codominant to eachother IA and IB are dominant to I Type AB is known as the “Universal Acceptor” Type O is known as the “Universal donor”

More Complex Patterns Epistasis – Coat colors in dogs Gender determination – Sex chromosomes – Autosomes Dosage compensation – Chromosome inactivation Barr bodies and Calico cats

XX and YY Chart To return to the chapter summary click escape or close this document.

Sex-Linked Traits Muscular dystrophy Color-blindness Hemophelia Different from sex-influenced traits

More Complex Patterns Polygenic Inheritance – Range in phenotypes – Examples: Height Eye color Skin color Environmental influence

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Chapter 11: Complex Inheritance Patterns and Human Genetics Section 3: Chromosomes and Human Heredity

Abnormal Numbers of Chromosomes How? Nondisjunction during Meiosis I – Monosomy – Trisomy – Polyploidy – Down syndrome

Nondisjunction

Detecting Genetic Disorders Genetic counseling Fetal testing – Amniocentesis – Chorionic villi sampling Karyotyping

Karyotype 1

Karyotype 2

Turner’s Syndrome

Klinefelter’s Syndrome

Karyotype 4