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

Complex Inheritance and Human Heredity Cystic Fibrosis  Affects the mucus-producing glands; body can’t get rid of mucus 11.1 Basic Patterns of Human Inheritance Chapter 11 Albinism  Caused by altered genes, resulting in the absence of the skin pigment melanin in hair and eyes

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

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

Complex Inheritance and Human Heredity 11.1 Basic Patterns of Human Inheritance Chapter 11

Complex Inheritance and Human Heredity Pedigrees  A diagram that traces the inheritance of a particular trait through several generations 11.1 Basic Patterns of Human Inheritance Chapter 11

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

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

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

Complex Inheritance and Human Heredity Sickle-cell Disease  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 Normal red blood cell 7766x 11.2 Complex Patterns of Inheritance Chapter 11

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

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

Complex Inheritance and Human Heredity Coat Color of Rabbits Light gray Dark gray Himalayan Albino Chinchilla 11.2 Complex Patterns of Inheritance Chapter 11

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

Complex Inheritance and Human Heredity Sex-Linked Traits  Genes located on the X chromosome  Red-green color blindness  Hemophilia 11.2 Complex Patterns of Inheritance Chapter 11 Sex-Linked Traits

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