Chapter 11 Complex Inheritance and Human Heredity 11

Chapter 11 Complex Inheritance and Human Heredity 11. 1 Basic Patterns of Human Inheritance Recessive Genetic Disorders § A recessive trait is expressed when the individual is homozygous recessive for the trait.

Chapter 11 Complex Inheritance and Human Heredity 11. 1 Basic Patterns of Human Inheritance Cystic Fibrosis § Affects the mucus-producing glands; body can’t get rid of mucus Albinism § Caused by altered genes, resulting in the absence of the skin pigment melanin in hair and eyes

Chapter 11 Complex Inheritance and Human Heredity 11. 1 Basic Patterns of Human Inheritance Tay-Sachs Disease § Caused by the absence of the enzymes responsible for breaking down fatty acids § Fat accumulates in the brain, inflating brain nerve cells and causing mental deterioration.

Chapter 11 Complex Inheritance and Human Heredity 11. 1 Basic Patterns of Human Inheritance Dominant Genetic Disorders § Huntington’s disease affects the nervous system. § Achondroplasia causes small body size and limbs that are comparatively short.

Chapter 11 Complex Inheritance and Human Heredity 11. 1 Basic Patterns of Human Inheritance

Chapter 11 Complex Inheritance and Human Heredity 11. 1 Basic Patterns of Human Inheritance Pedigrees § A diagram that traces the inheritance of a particular trait through several generations

Chapter 11 Complex Inheritance and Human Heredity 11. 1 Basic Patterns of Human Inheritance Predicting Disorders § Helps scientists in following inheritance patterns and determining phenotypes and genotypes.

Chapter 11 Complex Inheritance and Human Heredity 11. 2 Complex Patterns of Inheritance Incomplete Dominance § The heterozygous phenotype is an intermediate phenotype between the two homozygous phenotypes.

Chapter 11 Complex Inheritance and Human Heredity 11. 2 Complex Patterns of Inheritance Codominance § Both alleles are expressed in the heterozygous condition.

Chapter 11 Complex Inheritance and Human Heredity 11. 2 Complex Patterns of Inheritance Sickle-cell Disease Normal red blood cell § Changes in hemoglobin cause red blood cells to change to a sickle shape. § People who are heterozygous for the trait have both normal and sickle-shaped cells. Sickle cell 7766 x

Chapter 11 Complex Inheritance and Human Heredity 11. 2 Complex Patterns of Inheritance Multiple Alleles § Blood groups in humans § ABO blood groups have three forms of alleles.

Chapter 11 Complex Inheritance and Human Heredity 11. 2 Complex Patterns of Inheritance Coat Color of Rabbits § Multiple alleles can demonstrate a hierarchy of dominance. § In rabbits, four alleles code for coat color: C, cch, and c.

Chapter 11 Complex Inheritance and Human Heredity 11. 2 Complex Patterns of Inheritance Coat Color of Rabbits Chinchilla Albino Light gray Dark gray Himalayan

Chapter 11 Complex Inheritance and Human Heredity 11. 2 Complex Patterns of Inheritance Sex Determination § Sex chromosomes determine an individual’s gender.

Chapter 11 Complex Inheritance and Human Heredity 11. 2 Complex Patterns of Inheritance Sex-Linked Traits § Genes located on the X chromosome § Red-green color blindness § Hemophilia Sex-Linked Traits

Chapter 11 Complex Inheritance and Human Heredity 11. 3 Chromosomes and Human Heredity Karyotype Studies § Karyotype—graph of homologous chromosomes arranged in decreasing size.