CHAPTER 11 11-1 BASIC PATTERNS IN HUMAN INHERITANCE Objectives 1.Analyze genetic patterns to determine dominant or recessive inheritance patterns 2.Summarize.

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  • CHAPTER 11

  • 11-1 BASIC PATTERNS IN HUMAN INHERITANCEObjectivesAnalyze genetic patterns to determine dominant or recessive inheritance patternsSummarize examples of dominant and recessive disordersConstruct human pedigrees from genetic information

  • 11.1 Basic Patterns of Human InheritanceComplex Inheritance and Human HeredityChapter 11Recessive Genetic DisordersA recessive trait is expressed when the individual is homozygous recessive for the trait.

  • Complex Inheritance and Human HeredityCystic Fibrosis Affects the mucus-producing glands, digestive enzymes, and sweat glands Chloride ions are not absorbed into the cells of a person with cystic fibrosis but are excreted in the sweat. Without sufficient chloride ions in the cells, a thick mucus is secreted. 11.1 Basic Patterns of Human InheritanceChapter 11

  • Complex Inheritance and Human HeredityAlbinismCaused by altered genes, resulting in the absence of the skin pigment melanin in hair and eyes White hairVery pale skinPink pupils11.1 Basic Patterns of Human InheritanceChapter 11

  • Complex Inheritance and Human HeredityTay-Sachs Disease Caused by the absence of the enzymes responsible for breaking down fatty acids called gangliosides Gangliosides accumulate in the brain, inflating brain nerve cells and causing mental deterioration. 11.1 Basic Patterns of Human InheritanceChapter 11

  • Complex Inheritance and Human HeredityGalactosemia Recessive genetic disorder characterized by the inability of the body to digest galactose. 11.1 Basic Patterns of Human InheritanceChapter 11

  • Complex Inheritance and Human HeredityDominant Genetic Disorders Huntingtons disease affects the nervous system. Achondroplasia is a genetic condition that causes small body size and limbs that are comparatively short.11.1 Basic Patterns of Human InheritanceChapter 11

  • Complex Inheritance and Human Heredity11.1 Basic Patterns of Human InheritanceChapter 11

  • Complex Inheritance and Human HeredityChapter 11

  • Complex Inheritance and Human HeredityPedigreesA diagram that traces the inheritance of a particular trait through several generations 11.1 Basic Patterns of Human InheritanceChapter 11

  • Complex Inheritance and Human HeredityInferring Genotypes Knowing physical traits can determine what genes an individual is most likely to have. Predicting Disorders Record keeping helps scientists use pedigree analysis to study inheritance patterns, determine phenotypes, and ascertain genotypes.11.1 Basic Patterns of Human InheritanceChapter 11

  • 11-2 COMPLEX PATTERNS OF INHERITANCEObjectivesDistinguish between various complex inheritance patternsAnalyze sex-linked and sex-limited inheritance patternsExplain how the environment can influence the phenotype of an organism

  • 11.2 Complex Patterns of InheritanceComplex Inheritance and Human HeredityIncomplete DominanceThe heterozygous phenotype is an intermediate phenotype between the two homozygous phenotypes. Chapter 11

  • Complex Inheritance and Human HeredityCodominanceBoth alleles are expressed in the heterozygous condition. 11.2 Complex Patterns of InheritanceChapter 11

  • Complex Inheritance and Human HereditySickle-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 cellNormal red blood cell7766x11.2 Complex Patterns of InheritanceChapter 11

  • Complex Inheritance and Human HeredityMultiple AllelesBlood groups in humans ABO blood groups have three forms of alleles.11.2 Complex Patterns of InheritanceChapter 11

  • Complex Inheritance and Human HeredityCoat Color of RabbitsMultiple alleles can demonstrate a hierarchy of dominance.In rabbits, four alleles code for coat color: C, cch, ch, and c.11.2 Complex Patterns of InheritanceChapter 11

  • Complex Inheritance and Human HeredityCoat Color of Rabbits Light grayDark grayHimalayanAlbinoChinchilla11.2 Complex Patterns of InheritanceChapter 11

  • Complex Inheritance and Human HeredityEpistasisVariety is the result of one allele hiding the effects of another allele. No dark pigment present in furDark pigment present in fureebbeeB_E_bbE_B_11.2 Complex Patterns of InheritanceChapter 11

  • Complex Inheritance and Human HereditySex Determination Sex chromosomes determine an individuals gender. 11.2 Complex Patterns of InheritanceChapter 11

  • Complex Inheritance and Human HeredityDosage Compensation The X chromosome carries a variety of genes that are necessary for the development of both females and males. The Y chromosome mainly has genes that relate to the development of male characteristics. Chromosome inactivation Barr bodies 11.2 Complex Patterns of InheritanceChapter 11

  • Complex Inheritance and Human HereditySex-Linked TraitsGenes located on the X chromosome Red-green color blindness Hemophilia 11.2 Complex Patterns of InheritanceChapter 11Sex-Linked Traits

  • Complex Inheritance and Human HeredityPolygenic TraitsPolygenic traits arise from the interaction of multiple pairs of genes. 11.2 Complex Patterns of InheritanceChapter 11

  • Complex Inheritance and Human HeredityEnvironmental Influences Environmental factorsDiet and exerciseSunlight and waterTemperature11.2 Complex Patterns of InheritanceChapter 11

  • Complex Inheritance and Human HeredityTwin StudiesHelps scientists separate genetic contributions from environmental contributions Traits that appear frequently in identical twins are at least partially controlled by heredity.Traits expressed differently in identical twins are strongly influenced by environment.11.2 Complex Patterns of InheritanceChapter 11

  • Karyotypemicrograph in which the pairs of homologous chromosomes are arranged in decreasing size.11.3 Chromosomes and Human HeredityComplex Inheritance and Human HeredityKaryotype StudiesImages of chromosomes stained during metaphase Chromosomes are arranged in decreasing size to produce a micrograph. Chapter 11

  • Complex Inheritance and Human HeredityTelomeresTelomere caps consist of DNA associated with proteins. Serves a protective function for the structure of the chromosome 11.3 Chromosomes and Human HeredityChapter 11

  • Complex Inheritance and Human HeredityNondisjunctionCell division during which sister chromatids fail to separate properly Down syndrome11.3 Chromosomes and Human HeredityChapter 11Visualizing Nondisjunction

  • Complex Inheritance and Human HeredityChapter 11

    *Option 2 (continued on the next slide)*Option 2

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