Basic Patterns of Human InheritanceComplex Inheritance and Human HereditySection 1Recessive Genetic DisordersA recessive trait is expressed when the individual is homozygous recessive for the trait.

Complex Inheritance and Human HereditySection 1

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. Basic Patterns of Human InheritanceSection 1

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 pupilsBasic Patterns of Human InheritanceSection 1

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. Basic Patterns of Human InheritanceSection 1

Complex Inheritance and Human HeredityGalactosemia Recessive genetic disorder characterized by the inability of the body to digest galactose. Basic Patterns of Human InheritanceSection 1

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.Basic Patterns of Human InheritanceSection 1

Complex Inheritance and Human HeredityBasic Patterns of Human InheritanceSection 1

Complex Inheritance and Human HereditySection 1

Complex Inheritance and Human HeredityPedigreesA diagram that traces the inheritance of a particular trait through several generations Basic Patterns of Human InheritanceSection 1

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.Basic Patterns of Human InheritanceSection 1

Complex Patterns of InheritanceComplex Inheritance and Human HeredityIncomplete DominanceThe heterozygous phenotype is an intermediate phenotype between the two homozygous phenotypes. Section 2

Complex Inheritance and Human HeredityCodominanceBoth alleles are expressed in the heterozygous condition. Complex Patterns of InheritanceSection 2Sickle-cell disease is one example.

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 cell7766xComplex Patterns of InheritanceSection 2

Complex Inheritance and Human HeredityMultiple AllelesBlood groups in humans ABO blood groups have three forms of alleles.Complex Patterns of InheritanceSection 2

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.Complex Patterns of InheritanceSection 2

Complex Inheritance and Human HeredityEpistasisVariety is the result of one allele hiding the effects of another allele. Complex Patterns of InheritanceSection 2

Complex Inheritance and Human HereditySex Determination Sex chromosomes determine an individuals gender. Complex Patterns of InheritanceSection 2

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. In females, one X chromosome is inactivated in each cell. The inactivated X chromosome is visible in stained cells as a Barr body.Complex Patterns of InheritanceSection 2

Complex Inheritance and Human HereditySex-Linked TraitsGenes located on the X chromosome Red-green color blindness Hemophilia Complex Patterns of InheritanceSection 2Sex-Linked Traits

Complex Inheritance and Human HeredityPolygenic TraitsPolygenic traits arise from the interaction of multiple pairs of genes. Complex Patterns of InheritanceSection 2

Complex Inheritance and Human HeredityEnvironmental Influences Environmental factors influence an organisms phenotypeDiet and exerciseSunlight and waterTemperatureComplex Patterns of InheritanceSection 2

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.Complex Patterns of InheritanceSection 2

Karyotypemicrograph in which the pairs of homologous chromosomes are arranged in decreasing size.Chromosomes and Human HeredityComplex Inheritance and Human HeredityKaryotype StudiesImages of chromosomes stained during metaphase Chromosomes are arranged in decreasing size to produce a micrograph. Section 3

Complex Inheritance and Human HeredityTelomeresTelomere caps consist of DNA associated with proteins. Serves a protective function for the structure of the chromosome Chromosomes and Human HereditySection 3

Complex Inheritance and Human HeredityNondisjunctionCell division during which sister chromatids fail to separate properly Down syndrome, also called trisomy 21Chromosomes and Human HereditySection 3

Complex Inheritance and Human HeredityChapter Resource MenuChapter Diagnostic QuestionsFormative Test QuestionsChapter Assessment QuestionsStandardized Test Practiceconnected.mcgraw-hill.comGlencoe Biology TransparenciesImage BankVocabularyAnimationClick on a hyperlink to view the corresponding feature.Chapter

ABCDCDQ 1 albinism cystic fibrosis galactosemia Tay-SachsIdentify the disease characterized by the absence of melanin. Complex Inheritance and Human HeredityChapterChapter Diagnostic Questions

ABCDCDQ 2Complex Inheritance and Human HeredityChapterChapter Diagnostic Questions excessive mucus production an enlarged liver a cherry-red spot on the back of the eye vision problemsAn individual with Tay-Sachs disease would be identified by which symptom?

ABCDCDQ 3Complex Inheritance and Human HeredityChapterChapter Diagnostic QuestionsUnder what circumstances will a recessive trait be expressed? A recessive allele is passed on by both parents. One parent passes on the recessive allele. The individual is heterozygous for the trait. There is a mutation in the dominant gene.

ABCDFQ 1Complex Inheritance and Human HeredityChapterIt appears at birth and runs in families. It is linked to an enzyme deficiency.It continues throughout a patients life, affecting bones and joints.It is caused by acid excretion and results in black urine.Which of Dr. Garrods observations about alkaptonuria was most critical to his determination that it is a genetic disorder?Section 1 Formative Questions

ABCDFQ 2Complex Inheritance and Human HeredityChapter DD Dd dd dEWhich is the genotype of a person who is a carrier for a recessive genetic disorder?Section 1 Formative Questions

ABCDFQ 3Complex Inheritance and Human HeredityChapterSection 1 Formative Questions at least one parent is a carrier both parents are carriers both parents are homozygous recessive at least one parent is homozygous dominantAlbinism is a recessive condition. If an albino squirrel is born to parents that both have normal fur color, what can you conclude about the genotype of the parents?

ABCDFQ 4Complex Inheritance and Human HeredityChapter dosage compensation incomplete dominance multiple alleles sex-linkedWhen a homozygous male animal with black fur is crossed with a homozygous female with white fur, they have offspring with gray fur. What type of inheritance does this represent?Section 2 Formative Questions

ABCDFQ 5Complex Inheritance and Human HeredityChapterSection 2 Formative Questions autosomes Barr bodies monosomes sex chromosomesOf the 23 pairs of chromosomes in human cells, one pair is the _______.

ABCDFQ 6Complex Inheritance and Human HeredityChapterSection 2 Formative Questions blood type color blindness hemophilia skin colorWhich is an example of a polygenic trait?

ABCDFQ 7Complex Inheritance and Human HeredityChapter The blood type of an individual. The locations of genes on a chromosome. The cells chromosomes arranged in order. The phenotype of individuals in a pedigree.What does a karyotype show?Section 3 Formative Questions

ABCDFQ 8Complex Inheritance and Human HeredityChapterSection 3 Formative Questions multiple alleles nondisjunction nonsynapsis trisomyWhat is occurring in this diagram?

ABCDFQ 9Complex Inheritance and Human HeredityChapterSection 3 Formative Questions Down syndrome Klinefelters syndrome Tay-Sachs syndrome Turners syndromeWhat condition occurs when a persons cells have an extra copy of chromosome 21?

ABCDCAQ 1Complex Inheritance and Human HeredityChapter 1 and 2 are siblings 1 and 2 are parents 1 and 2 are offspring 1 and 2 are carriersWhat does the top horizontal line between numbers 1 and 2 in the figure indicates?Chapter Assessment Questions

ABCDCAQ 2Complex Inheritance and Human HeredityChapterChapter Assessment Questions IA IO IB iWhich is not an allele in the ABO blood group?

ABCDCAQ 3Complex Inheritance and Human HeredityChapterChapter Assessment Questions one less chromosome on pair 12 one extra chromosome on pair 21 one less chromosome on pair 21 one extra chromosome on pair 12Down Syndrome results from what change in chromosomes?

ABCSTP 1Complex Inheritance and Human HeredityChapter heterozygous homozygous dominant homozygous recessiveIf a genetic disorder is caused by a dominant allele, what is the genotype of those who do not have the disorder?Standardized Test Practice

ABCSTP 2Complex Inheritance and Human HeredityChapterStandardized Test Practice RR Rr rrAnalyze this pedigree showing the inheritance of a dominant genetic disorder. Which would be the genotype of the first generation father?

ABCDSTP 3Complex Inheritance and Human HeredityChapterStandardized Test Practice codominance dosage compensation epistasis sex-linkedShorthorn cattle have an allele for both red and white hair. When a red-haired cow is crossed with a white-haired bull, their calf has both red and white hairs scattered over its body. What type of inheritance does this represent?

ABCDSTP 4Complex Inheritance and Human HeredityChapterStandardized Test Practice Males have only one X chromosome. Males have two X chromosomes. Males have only one Y chromosome. The traits are located on the Y chromosomes.Why are males affected by recessive sex-linked traits more often than are females?

ABCDSTP 5Complex Inheritance and Human HeredityChapterStandardized Test Practice 25% 50% 75% 100%A carrier of hemophilia and her husband, who is unaffected by the condition, are expecting a son. What is the probability that their son will have hemophilia?

carrierpedigreeComplex Inheritance and Human HereditySection 1VocabularySection 1

incomplete dominancecodominancemultiple allelesepistasissex chromosomeautosomesex-linked traitpolygenic traitComplex Inheritance and Human HereditySection 2VocabularySection 2

karyotypetelomerenondisjunctionComplex Inheritance and Human HereditySection 3VocabularySection 3

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