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UNIT 9 – THE HUMAN GENOME Test Tuesday 2-14-12 (chapter 14) I. HUMAN GENETICS (pp. 341-343) A. Human Somatic Cells body or __. diploid 2n ________ cells are ______ 46 chromosomes, Each cell contains ___ 23 pairs of chromosomes. or ___ 22 are ____________, – Of the pairs, ___ homologous contain the same genes in the same order, and are called ____________. autosomes A. Human Somatic Cells The 23rd pair of chromosomes are the ____ sex chromosomes. – – Female =___ XX Male= ___. XY B. Human Gametes n and Gametes are _______, haploid or __, 23 chromosomes. contain ___ egg cells made Female gametes are _____ ovaries in the ___________ in the process of __________. meiosis sperm Male gametes are ______cells made in the _________ in the process of testes meiosis __________. B. Human Gametes Egg cell can only contain an __ X chromosome Sperm cell produced has a ___% 50 chance of Y and a ___% containing a ___ chance of 50 containing an __. X – The _____ male determines the sex of the offspring. C. Analyzing Human Chromosome Numbers Nondisjunction - Abnormal numbers of chromosomes in gametes ______ result in genetic number disorders disorders called ___________. nondisjunction ____________, which means ______________. “not coming apart” 1. C. Analyzing Human Chromosome Numbers A chromosome pair fails to separate anaphase so the gametes correctly in ________ produced have an abnormal _____________________. number of chromosomes Number disorders are not inherited; therefore, they cannot be predicted Punnett squares with ________________. C. Analyzing Human Chromosome Numbers 2. Karyotypes – A karyotype is a photograph of ________________. chromosome pairs mitosis and are Cells are stopped during _________ stained, photographed, and the photograph is enlarged. C. Analyzing Human Chromosome Numbers The chromosomes are cut out and homologous pairs in size arranged in ____________ order, with the ____ sex chromosomes making up the 23rd pair. number disorders Used to detect _________ gender of an and to determine the ________ unborn child. C. Analyzing Human Chromosome Numbers They do not detect abnormal _______; genes therefore, a normal karyotype does not normal child! guarantee a ______ II. HUMAN GENETIC DISORDERS – NUMBER DISORDERS (pp. 352, 353) A. Autosomal Number Disorders Most are _____. lethal The only autosomal number disorder that allows survival into adulthood is Down syndrome ___________________. Is there a problem with this karotype A. Autosomal Number Disorders Down syndrome Down syndrome trisomy 21 because known as __________ there are ___ 3 chromosomes at the 21st position, instead of ___. 2 ____ Individuals have characteristic facial features; growth, behavior, and mental development are all affected Autosomal Number Disorders Down syndrome There is also a higher risk of _________ congenital heart defects. The incidence of babies with Down syndrome is much o higher in ______ older l mothers. Is there a problem with this karyotype? B. Sex Chromosome Number Disorders 1. Turner Syndrome 45 XO Called ______ because individuals lack __________________. 2nd sex chromosome _______, female typically ______ short in stature, underdeveloped sexually, sterile with a normal life ______, expectancy. Does this individual have a number disorder? B. Sex Chromosome Number Disorders 2. Klinefelter Syndrome Called ________. 47 XXY Symptoms do not appear until ________ pubertyat which time affected _________ males show poor sexual development and infertility. testosterone Treated with __________. Normal life expectancy. III. ANALYSIS OF HUMAN INHERITANCE A. Punnett Squares & Multiple Alleles (pp. 345-346) more than 2 1. multiple alleles; that is, ___________ alleles. An example of this is ABO blood groups. 3 alleles for this gene. Two of the There are ____ alleles, A _______ and B are co-dominant, meaning they always show if present. The third allele, ______________ ____, i (o) is recessive, meaning it will only show if the genotype is ___. ii – . Punnett Squares & Multiple Alleles (pp. 345-346) 2 alleles for Each individual inherits ___ this gene, one from _____ mom and one dad from ____. Punnett Squares & Multiple Alleles (pp. 345-346) The possibilities for blood group genotypes and phenotypes are: Phenotypes Genotypes A A A I I or I i Type A blood _____________ B B B Type B blood _____________ I I or I i A B I I Type AB blood _____________ ii Type O blood _____________ Complete ABO Blood Type Punnetts in Notes packet B. Pedigrees A pedigree is a diagram that follows the trait through several inheritance of a single _____ generations of a family. ____________ – – squares Males are represented by ________ circles Females, by _______. Individuals with the trait are represented shaded figures. with ________ B. Pedigrees Individuals shown with unshaded figures _________________. do not show the trait parents and children Vertical lines connect _______ _______. spouses or Horizontal lines connect _________ siblings _________. birth order Children are placed in __________,from left to right _________. Complete pedigrees in note packet IV. INHERITED HUMAN GENETIC DISORDERS Gene Mutations a change in the DNA sequence of the gene ______________________________. A. Causes Inherited human genetic disorders IV. INHERITED HUMAN GENETIC DISORDERS B. Types of Inherited Genetic Disorders 1. Autosomal Genetic Disorders – Gene mutation is on any chromosome other than sex chromosomes ________________ 2. Sex-Linked Disorders – Mutated gene is on X chromosome. the ____ VI. GENETIC DISORDERS - AUTOSOMAL DISORDERS (pp. 345-348) autosomes Most genes are carried on the ___________, 44 ______ chromosomes other than the sex chromosomes. autosomal Most genetic disorders are ___________ disorders. These disorders affect males and females equally and are due to _____ gene mutations. ________ Autosomal disorders can be divided into three groups based on the pattern of inheritance. 1. Autosomal Recessive 2. Autosomal Co-Dominant 3. Autosomal Dominant A. Autosomal Recessive Disorders 1. Albinism – Characterized by failure to produce pigment, __________. Affected melanin eyes _____, skin individuals lack coloration in ______, and _____. Very susceptible to ___________. hair UV light Normal Symptoms appear __________; _________ life at birth expectancy A. Autosomal Recessive Disorders 2. Cystic Fibrosis – Characterized by excess mucus production __________________in _______, lungs _________system. digestive Symptoms appear just after birth and include frequent respiratory infections, poor nutrition. With treatment, patients can survive to young adulthood. Cystic fibrosis is fatal the most common _______ genetic disorder in the United States among Caucasians. ________ B. Autosomal Co-Dominant Disorders Sickle cell anemia is an autosomal cohemoglobin dominant disorder that affects __________ production. oxygen to Hemoglobin is the protein that binds ________ red blood cells. 1. Sickle cell Anemia Individuals with the normal genotype, AA, do not have the sickle cell allele and produce only normal Hemoglobin. Sickle cell Anemia Individuals that are SS produce abnormal hemoglobin that causes the red blood cells to “sickle” when oxygen availability is decreased; – for example, in high altitudes or during periods of stress. Sickled RBCs are more fragile, easily destroyed – results in energy due to decreased _____ ATP production in lack of ________ cells, blockage of blood vessels, and severe pain. Shortened life expectancy. Most common inherited disease African ancestry. in individuals of ______ Sickle cell Anemia Heterozygotes (AS) produce both normal and abnormal hemoglobin and are said to have ________________. They do not show symptoms of sickle cell trait the disorder. In certain areas, individuals with sickle cell trait have a benefit over individuals that lack the sickle cell allele because they are resistant to malaria _______. Malaria is a serious, sometimes fatal disease spread by mosquitoes __________ that affects millions of people each year in _______. Africa This increased malarial resistance has resulted in a very high incidence of AS individuals. If two heterozygotes 25 marry and have children, they have a ___% chance of having a child with sickle cell anemia. C. Autosomal Dominant Disorders 1. Huntington’s Disease – Fatal genetic disorder in which symptoms do not show 30s to 40s until ______________. Characterized by deterioration of _____________. nervous system Dwarfism 2. Achondroplasia - ___________ V. GENETIC DISORDERS - SEXLINKED DISORDERS A. Sex-Linked Inheritance (pp.350, 351) “Sex-linked” if it is located on a sex X or Y chromosome (______). In humans, sex-linked genes are almost X chromosome. always located on the larger ___ Y chromosome is much smaller and carries – The __ only a few genes related to male sexual development ________________________. A. Sex-Linked Inheritance (pp.350, 351) 2 X chromosomes; Females have __ one males have ____. Females will only show recessive traits located on the X chromosome if they are ________________________. homozygous recessive Males will always show a recessive trait located on the one X X chromosome because he only has _____ chromosome, – genes on the X chromosome will show. so all _______ males having a much higher This results in _________ incidence of sex-linked disorders. A. Sex-Linked Inheritance 1. Genotypes Genotypes for sex-linked traits are written using the X and Y chromosomes to show path of inheritance. – – – For example, male-pattern baldness is a sex-linked recessive trait. hIf H = normal head of hair and h = baldness, h h X Y bald male = _____; bald female = _____. X X carriers for sex-linked recessive disorders. Females can be _______ it does not show A carrier has the defective allele, but ______________. H h The genotype of a female carrier is ______. X X cannot be carriers for sex-linked traits because Males _______ their 2nd sex chromosome is the naked _______! Y 2. Sex-Linked Punnett Squares In sex-linked traits, probabilities for male and female offspring must be calculated separately because traits are inherited differently ________________. If a man with a full head of hair marries a woman who is heterozygous, what is the probability they would have a son who would go bald? A daughter? B. Sex-Linked Disorders All of these disorders are sex-linked recessive ___________________. 1. Color Blindness – Inability to differentiate and distinguish colors ___________________. Results For Ishihara Test(above) Normal Color Vision Red-Green Color Blind Left Right Left Right Spots Top 25 29 Top 25 Middle 45 56 Middle Spots 56 8 Bottom Spots Spots Bottom 6 B. Sex-Linked Disorders 2. Hemophilia – Missing an enzyme required clotting - results in for normal blood ____________ uncontrolled bleeding Treated with _____________________. blood transfusions, injections of missing factor. B. Sex-Linked Disorders 3. Duchenne’s Muscular Dystrophy – Symptoms develop at ___________. 3-6 years Muscles _____________________ weaken, break down _, leading to eventual death. No available treatment or ______. cure __________ Death usually occurs before adulthood.