2 Section 14-1: Human Heredity Key Concepts: How is sex determined?How do small changes in DNA Cause genetic disorders?Human ChromosomesA. Karyotype: A picture of chromosomes taken during mitosis and cut out and arranged into homologous pairs.
3 Diploid Cell: ________ of homologous chromosomes Human diploid cell has ____ chromosomes arranged in ____ pairsThe 46 chromosomes containTwo sets46236 billion nucleotide pairsMendelian genetics requires that organismsof gene from each parentinherit a single copyIn humans, _______________ (reproductive cells of egg and sperm) contain a single copy of each gene (one set of genetic information).the gametes
4 Gametes are formed in the __________ (sperm) and __________(egg) by meiosis. Each gamete contains 23 chromosomes (one set) or __________________ (N) of chromosomes.________________ requires the egg and the sperm to join and produce a ______________ (fertilized egg) that contains 46 chromosomes (two sets) or _____________________ (2N).testesovarieshaploid numberFertilizationzygotediploid number
5 Humans have 46 total chromosomes 44 _____________ follow regular Mendelian genetics2 _________________ (X and Y) are sex-linkedautosomessex chromosomesPedigree Chart: A pedigree chart shows the _________________ within a family and can be useful to help with __________________________ within families. It is another ___________________________ of a particular cross and the genotype of the family members.relationshipgenetic inheritance problemsway to predict theoutcome
6 Pedigree Figure 14-3 A Pedigree Section 14-1 A circle represents a female.A square represents a male.A horizontal line connecting a male and female represents a marriage.A vertical line and a bracket connect the parents to their children.A half-shaded circle or square indicates that a person is a carrier of the trait.A circle or square that is not shaded indicates that a person neither expresses the trait nor is a carrier of the trait.A completely shaded circle or square indicates that a person expresses the trait.
7 Human TraitsPhenotypes are determined by genotype as well as ________________________________.________________________________ on gene expression are not inherited, but genes are.environmentally influencedEnvironmental influences
8 III. Human GenesThe __________________: Complete set of genetic informationComposed of about 30,000 geneshuman genomeBlood Group GenesHuman Blood comes in a variety of genetically determined blood groupsThere are many different types of blood groups but the ones associated with the ABO blood group and the Rh blood groups are best known..
9 Rh blood groups is controlled by single gene with ________________ Rh blood groups is controlled by single gene with ________________. It is another antigen in blood, first discovered in Rhesus monkeys. The arrangement of the alleles determines only _______ possible types _____________ (+) contains the antigen, or ___________ (-) doesn’t contain the antigen. Positive is ______________ over negative.Rh-positive is identified with two genotypes: Rh+/Rh+ or Rh+/Rh-Rh-negative is identified with one genotype: Rh-/Rh-Two allelestwopositivenegativedominant
10 ABO Blood Groups: Discovered in 1900 by Karl Landsteiner ABO Blood Groups: Discovered in 1900 by Karl Landsteiner. He realized that all blood is classified into four types: ____, ____, ____, and _____ due to the presence of or absence of specific __________ in the blood.Alleles IA and IB are __________________ and io is ________________ to both IA and IBABABOantigenscodominantrecessiveAntigens are ______________________ used by the immune system. When an unrecognized antigen is present an immune response takes place and the cells ____________________________.chemical markers_clump or agglutinate
11 Blood Type and Antigen Interactions Figure 14-4 Blood GroupsBlood Type and Antigen InteractionsSection 14-1Safe TransfusionsPhenotype(Blood TypeAntigen onRed Blood CellGenotypeToFromGo to Section:
12 B. Recessive Alleles: Trait controlled by a recessive allele B. Recessive Alleles: Trait controlled by a recessive allele. This results in the disorder being present ___________________________.Examples include: PKU (Phenylketonuria), Tay Sachs disease and Cystic Fibrosis, Albinism, and Galactosemia (See chart on page 345)only if both alleles are recessive
13 C. Dominant Alleles: Traits controlled by a dominant allele C. Dominant Alleles: Traits controlled by a dominant allele. This results in the disorder being present when __________________________.Examples include: Achondroplasia (dwarfism), Hypercholesterolemia, and Huntington’s Diseaseonly one allele is present
15 Huntington Disease:It is controlled by a _________________________. The gene is located on Chromosome #4.single dominant alleleGenetic degenerative disease that shows no symptoms until a person is in their ____________________. It progresses with gradual degeneration of their nervous system leading to loss of muscle control and mental function until death occurs.thirties or forties
16 Question? Would you want to know now if you could potentially get Huntington’s disease when you are older? Would you want to know if you could pass the gene on to your offspring before you have children?A. Codominant Alleles: controlled by _______________________________________. Sickle Cell Anemia is such a disorder. (This will be discussed in detail later)two alleles that share dominance
17 IV. From Gene to Molecule The link between ______________________is not easily determined but for several diseases wehave been able to make the connection.For both _____________ and ________________a small change in the DNA of a _____________affects the ______________________, causing aserious genetic disorder.genetics and phenotypeCystic fibrosisSickle cell diseasesingle genestructure of a protein
18 A. Cystic Fibrosis: (See figure 14-8 p. 347) Cystic Fibrosis a.k.a. “CF” is a common genetic disease. It is most common in people of Northern European decent.It is a _______________________ of a gene found on the # 7 chromosome and affects the______________________________Recessive diseasedigestive and respiratory systems
19 It is caused by the____________________ in the middle of a sequence for a protein andcauses the protein to be ______________ anddoesn’t allow Chloride ions to transport acrossthe membrane, as they should. This causesthe cells in a person’s airways to be unable totransport chloride ions and become__________________.deletion of 3 basesabnormalclogged with mucus
20 Figure 14-8 The Cause of Cystic Fibrosis Section 14-1Chromosome # 7CFTR geneThe most common allele that causes cystic fibrosis is missing 3 DNA bases. As a result, the amino acid phenylalanine is missing from the CFTR protein.Normal CFTR is a chloride ion channel in cell membranes. Abnormal CFTR cannot be transported to the cell membrane.The cells in the person’s airways are unable to transport chloride ions. As a result, the airways become clogged with a thick mucus.
21 B. Sickle Cell AnemiaThe patient’s blood cells were found to beirregularly shaped, ____________________,and this is how the disease got its name.In normal red blood cells the____________________ carries ___________and distributes it around the body. In sickle celldisease, the red blood cells are sickle–shaped,causing the blood hemoglobin to no longer carryoxygen as well and _____________________like a sicklehemoglobin moleculeoxygendisrupts the normal functioning of the bodies cells, tissues and organs
22 This person is deprived of oxygen and the result is physical weakness, and damage to the brain, heart, spleen. It may be fatal.The cause: A _________________ in the DNA that codes for Hemoglobin polypeptides is changed. This substitutes Valine for glutamic acid.This change makes the hemoglobin less soluble in blood. This will cause the hemoglobin to come out of the blood and _______________. This crystallization causes the ________________ of the blood cells and the medical consequences.single basecrystallizesickle shape
23 The genetics: The allele for sickle cell (HS) is ___________ with the allele for normal hemoglobin (HA).codominantHeterozygotes (HS HA) are said to be ____ ____ __________ and have some effects of the disorder because they have both normal and sickle cell blood hemoglobin.Sickle cellcarriers
24 DNA normal hemoglobin CAC GTG GAC TGA GGA CTC CTC Messenger RNA sequenceGUG CAC CUG ACU CCU GAG GAGNormal hemoglobin amino acid sequenceVal – His – Leu – Thr – Pro – Glu – Glu……146DNA Sickle Cell AnemiaCAC GTG GAC TGA GGA CAC CTCMessenger RNA sequenceGUG CAC CUG ACU CCU GAGVal – His – Leu – Thr – Pro – – Glu……146
25 The distribution: Sickle Cell anemia is most prevalent in people of __________________. 10% of African Americans and 40% of populations in Africa and Asia carry the gene for Sickle cell anemia.Why? The carriers for the disease have a ___________________, a dangerous disease caused by a blood parasite found in tropical areas of the world.African descentresistance to Malaria
26 favored by natural selection Sickle Cell Anemia is a __________ that has provided an ____________ in Malaria prone areas and in these areas it is _______________________ and therefore Sickle Cell Anemia persists.mutationadvantagefavored by natural selectionHS HAHS HSHS HAHSHAHS HAHA HA
27 Section 14-2: Human Chromosomes Key concepts: Why are sex-linked disorders morecommon in males than in females?What is nondisjunction, and what problems does itcause?
28 6 billion base pairs Small part specific place several forms one I. Human Genes and ChromosomesHuman diploid cell contains ______________________ of DNA. All neatly packed into the 46 chromosomes.__________________ of the DNA actually functions as genes.Genes are located on the chromosomes and each gene occupies a ______________________ on a chromosome.Genes may exist in ____________________ (alleles)Each chromosome contains ______ of the alleles for each of its genesChromosome #21 and 22 are the ____________ of the human autosomes. These were the first two chromosomes whose sequences had been determined.6 billion base pairsSmall partspecific placeseveral formsonesmallest
29 Both also contain genes for some genetic disorders like ___________________________________________________We also discovered that there are many_________________________ segments of DNAHuman chromosomes also have________________ that can cross over just as wesaw in the fruit fly.Leukemia andAmyotrophic Lateral Sclerosis (ALS)non-coding, repeatingLinked genes
30 II. Sex-linked Genes1. _______________________ are the ones that__________ in males and females2. Chromosomes that are the ________ in male and females = _______________3. In humans: females = ____ and Males = ____4. The Y chromosome is smaller than the XSex ChromosomesdiffersameautosomesXXXY
31 A. Sex Determination1. Female _________ carry an X chromosome2. _________ gametes can carry either an X or Y (meiosis segregates the chromosomes; _______ of the sperm carry X and ______ of the sperm carry Y)3. In humans, _____________________________ of an offspringFemale: XXmale: XYgametesMale50%50%males determine the sexXYXXXXYXXXXY
32 In some animals such as birds, butterflies, and some fish, the female determines the sexbecause she has the __________ chromosomes.Sex-linked Genes1. In addition to determining the sex of an individual, the sex chromosomes carry genesthat ____________________differingaffect other traits.
33 Sex-linked Genetic Disorders May be on the X or Y chromosome, but Most often expressed in ____________because they only have one X chromosome and thus all the alleles are expressed even if they are recessive.usually on the X because the Y has very few genes.malesColorblindness is a recessive disorder in which people can’t distinguish between certain colors. ____________________ colorblindness is most common.XC and Xc are ________________ for normal and colorblind vision.Red-greenthe alleles
34 both normal vision females. XC XC and XC Xc areXC Xc is a _______________________ and can pass the gene on to her sons.Xc Xc is aXC Y is aXc Y is aboth normal vision females.carrier for colorblindnesscolorblind female.normal male andcolorblind male.
35 Colorblindness Figure 14-13 Colorblindness Section 14-2 Go to Section: Father(normal vision)Normal visionColorblindMaleFemaleDaughter(normal vision)Son(normal vision)Mother (carrier)Daughter(carrier)Son(colorblind)Go to Section:
36 Colorblindness Figure 14-13 Colorblindness Section 14-2 Go to Section: Father(normal vision)Normal visionColorblindMaleFemaleDaughter(normal vision)Son(normal vision)Mother (carrier)Daughter(carrier)Son(colorblind)Go to Section:
37 Hemophilia is a __________________________ in which one is unable to clot their blood. Also known asHemophilia is caused by a defect in a gene and the protein for normal blood clotting is missing.recessive sex-linked disorder“bleeders disease”.
40 Muscular Dystrophy is another Here the affected individual inherits a degenerative __________disorder.The gene that codes for a _____________ is defective. They rarely live past early adulthood.Treatments are being explored that ___________ the defective gene.sex-linked recessive disease.musclemuscle proteinreplace
41 III. X-Chromosomes Inactivation Males survive with only one X chromosome so, what do females do with 2? They ___________;it becomes inactive. This creates a dense region in the nucleus known as a ______________.This is seen in coat color in cats. The cells will randomly shut off the coat color allele in one X chromosome and turn them off in the other X chromosome in other cells and this leads to some areas that are spotted orange and some spotted black, creating a tricolor cat, ________. This only happens in __________ because males only have one X chromosome.shut one offBarr bodycalicofemales
42 IV. Chromosomal Disorders Whole/sets of chromosome mutations_______________ = failure of homologous chromosomes to separate normally during meiosisThis results in a disorder of __________________2. Examples of disorders include Down’s Syndrome, Klinefelter’s, and Turner’s SyndromeNondisjunctionchromosome number
43 Homologous chromosomes fail to separate NondisjunctionSection 14-2Homologous chromosomes fail to separateMeiosis I:NondisjunctionMeiosis IIGo to Section:
44 Homologous chromosomes fail to separate NondisjunctionSection 14-2Homologous chromosomes fail to separateMeiosis I:NondisjunctionMeiosis IIGo to Section:
45 Homologous chromosomes fail to separate NondisjunctionSection 14-2Homologous chromosomes fail to separateMeiosis I:NondisjunctionMeiosis IIGo to Section:
47 chromosome separation 2. Examples of disorders include Down’s Syndrome, Klinefelter’s, and Turner’s SyndromeNondisjunction disorders: Disorders in which the failure of _____________________ during one of the stages of meiosis causes a gamete to have _______________________________.Nondisjunction can occur in ___________________________.chromosome separationtoo few or too many chromosomesautosomes or sex chromosomes
48 nondisjunction of an autosome Down’s Syndrome: Down’s syndrome is an example of ____________________________, specifically chromosome 21.In Down’s syndrome there is an ___________ of chromosome 21 (trisomy 21).Doing a _____________ (display of all the chromosomes in a cell nucleus) and looking at the chromosomes under a microscope detect the extra chromosome.Characteristics of Down’s syndrome include _________________, physically challenged, facial irregularities, and often heart defects.nondisjunction of an autosomeextra copykaryotypemental retardation
50 Turners Syndrome: Nondisjunction of the sex chromosomes in which They have the chromosome makeup of _________ where “O” represents the missing chromosome.a chromosome is missing.45 XOThis individual is female in appearance but does not develop the female sex organs during puberty and is ________.sterile.
51 Klinefelter’s Syndrome: Nondisjunction of the sex chromosomes in which an _____________________ is present.They have the chromosome makeup of ________. They are ___________ in appearance and are also sterile. May also be 48 XXXY or 49 XXXXYextra X chromosome47XXYmaleNo nondisjunctions of the sex chromosomes have ever produced and survived without an ______________. This is because the X chromosome carries many genesX chromosomeessential for life.
52 Results mainly from nondisjunction in mother (67%) XXY conditionResults mainly from nondisjunction in mother (67%)Phenotype is tall malesSterile or nearly soFeminized traits (sparse facial hair, somewhat enlarged breasts)Treated with testosterone injections
54 The impact of the sex chromosome nondisjunction has led us to understand the importance of the _____________________ in determination of sex of an individual.This has recently been determined to be true because the Y chromosome has been found to have a gene that turns on ______________________ in the embryo even if many X chromosomes are present. Y chromosomemale sexual development