UNIT 9 – THE HUMAN GENOME

I. HUMAN GENETICS (pp. 311-313) A. Human Somatic Cells ________ cells are ______ or __. Each cell contains ___ chromosomes, or ___ pairs of chromosomes. Of the pairs, ___ are ____________, contain the same genes in the same order, and are called ____________. diploid body 2n 46 23 22 homologous autosomes

A. Human Somatic Cells sex XX The 23rd pair of chromosomes are the ____ chromosomes. Female =___ Male= ___. sex XX XY

B. Human Gametes n Gametes are _______, or __, and contain ___ chromosomes. Female gametes are _____ cells made in the ___________ in the process of __________. Male gametes are ______cells made in the _________ in the process of __________. haploid 23 egg ovaries meiosis sperm testes meiosis

B. Human Gametes Egg cell can only contain an __ chromosome Sperm cell produced has a ___% chance of containing a ___ and a ___% chance of containing an __. The _____ determines the sex of the offspring. X 50 Y 50 X male

C. Analyzing Human Chromosome Numbers Nondisjunction - Abnormal numbers of chromosomes in ______ result in genetic disorders called ___________. ____________, which means ______________. gametes number disorders nondisjunction “not coming apart”

C. Analyzing Human Chromosome Numbers A chromosome pair fails to separate correctly in ________ so the gametes produced have an abnormal _____________________. Number disorders are not inherited; therefore, they cannot be predicted with ________________. anaphase number of chromosomes Punnett squares

C. Analyzing Human Chromosome Numbers Karyotypes – A karyotype is a photograph of ________________. Cells are stopped during _________ and are stained, photographed, and the photograph is enlarged. chromosome pairs mitosis

C. Analyzing Human Chromosome Numbers The chromosomes are cut out and arranged in ____________ pairs in size order, with the ____ chromosomes making up the 23rd pair. Used to detect _________ disorders and to determine the ________ of an unborn child. homologous sex number gender

C. Analyzing Human Chromosome Numbers They do not detect abnormal _______; therefore, a normal karyotype does not guarantee a ______ child! genes normal

II. HUMAN GENETIC DISORDERS – NUMBER DISORDERS (pp. 313-314) A. Autosomal Number Disorders Most are _____. The only autosomal number disorder that allows survival into adulthood is ___________________. lethal Down syndrome

Is there a problem with this karotype

Autosomal Number Disorders Down syndrome known as __________ because there are ___ chromosomes at the ____ position, instead of ___. Individuals have characteristic facial features; growth, behavior, and mental development are all affected trisomy 21 3 21st 2

Autosomal Number Disorders Down syndrome There is also a higher risk of _________ heart defects. The incidence of babies with Down syndrome is much higher in ______ mothers. congenital ol older

Is there a problem with this karyotype?

B. Sex Chromosome Number Disorders 1. Turner Syndrome Called ______ because individuals lack __________________. _______, typically ______ in stature, underdeveloped sexually, ______, with a normal life expectancy. 45 XO 2nd sex chromosome female short sterile

Does this individual have a number disorder?

B. Sex Chromosome Number Disorders 2. Klinefelter Syndrome Called ________. Symptoms do not appear until ________ at which time affected _________ show poor sexual development and infertility. Treated with __________. Normal life expectancy. 47 XXY puberty males testosterone

III. ANALYSIS OF HUMAN INHERITANCE A. Punnett Squares & Multiple Alleles (pp. 304) multiple alleles; that is, ___________ alleles. An example of this is ABO blood groups. There are ____ alleles for this gene. Two of the alleles, _______ are co-dominant, meaning ______________ if present. The third allele, ____, is recessive, meaning it will only show if the genotype is ___. more than 2 3 A and B they always show i (o) ii

. Punnett Squares & Multiple Alleles 2 Each individual inherits ___ alleles for this gene, one from _____ and one from ____. mom dad

Punnett Squares & Multiple Alleles The possibilities for blood group genotypes and phenotypes are: Phenotypes Genotypes Type A blood _____________ Type B blood _____________ Type AB blood _____________ Type O blood _____________ I I or I i A I I or I i B I I A B ii

Complete ABO Blood Type Punnetts in Notes packet

B. Pedigrees (pp. 299-301) trait generations squares circles shaded A pedigree is a diagram that follows the inheritance of a single _____ through several ____________ of a family. Males are represented by ________ Females, by _______. Individuals with the trait are represented with ________ figures. trait generations squares circles shaded

B. Pedigrees Individuals shown with unshaded figures _________________. Vertical lines connect _______ and _______. Horizontal lines connect _________ or _________. Children are placed in __________,from _________. do not show the trait parents children spouses siblings birth order left to right

Complete pedigrees in note packet

IV. INHERITED HUMAN GENETIC DISORDERS Gene Mutations ______________________________. Causes Inherited human genetic disorders a change in the DNA sequence of the gene

IV. INHERITED HUMAN GENETIC DISORDERS B. Types of Inherited Genetic Disorders 1. Autosomal Genetic Disorders – Gene mutation is on any chromosome other than ________________ 2. Sex-Linked Disorders – Mutated gene is on the ____ chromosome. sex chromosomes X

VI. GENETIC DISORDERS - AUTOSOMAL DISORDERS autosomes Most genes are carried on the ___________, ______ chromosomes other than the sex chromosomes. Most genetic disorders are ___________ disorders. These disorders affect males and females ________ and are due to _____ mutations. 44 autosomal equally gene

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 (pp. 297) 1. Albinism – Characterized by failure to produce pigment, __________. Affected individuals lack coloration in ______, _____, and _____. Very susceptible to ___________. Symptoms appear __________; _________ life expectancy melanin eyes skin hair UV light Normal at birth

A. Autosomal Recessive Disorders 2. Cystic Fibrosis – Characterized by excess __________________in _______, _________system. Symptoms appear just after birth and include frequent respiratory infections, poor nutrition. With treatment, patients can survive to young adulthood. Cystic fibrosis is the most common _______ genetic disorder in the ________ among Caucasians. mucus production lungs digestive fatal United States

B. Autosomal Co-Dominant Disorders (pp. 303) Sickle cell anemia is an autosomal co-dominant disorder that affects __________ production. Hemoglobin is the protein that binds ________ to red blood cells. hemoglobin oxygen

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 lack of ________ due to decreased _____ production in cells, blockage of blood vessels, and severe pain. Shortened life expectancy. Most common inherited disease in individuals of ______ ancestry. energy ATP African

Sickle cell Anemia Heterozygotes (AS) produce both normal and abnormal hemoglobin and are said to have ________________. They do not show symptoms of 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 is a serious, sometimes fatal disease spread by __________ that affects millions of people each year in _______. This increased malarial resistance has resulted in a very high incidence of AS individuals. If two heterozygotes marry and have children, they have a ___% chance of having a child with sickle cell anemia. sickle cell trait malaria mosquitoes Africa 25

C. Autosomal Dominant Disorders (pp. 298) 1. Huntington’s Disease – Fatal genetic disorder in which symptoms do not show until ______________. Characterized by deterioration of _____________. 2. Achondroplasia - ___________ 30s to 40s nervous system Dwarfism

V. GENETIC DISORDERS - SEX-LINKED DISORDERS (pp. 305-308) A. Sex-Linked Inheritance “Sex-linked” if it is located on a sex chromosome (______). In humans, sex-linked genes are almost always located on the larger ___ chromosome. The __ chromosome is much smaller and carries only a few genes related to ________________________. X or Y X Y male sexual development

A. Sex-Linked Inheritance (pp. 305-308) 2 Females have __ X chromosomes; males have ____. Females will only show recessive traits located on the X chromosome if they are ________________________. Males will always show a recessive trait located on the X chromosome because he only has _____ X chromosome, so all _______ on the X chromosome will show. This results in _________ having a much higher incidence of sex-linked disorders. one homozygous recessive one genes males

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. If H = normal head of hair and h = baldness, bald male = _____; bald female = _____. Females can be _______ for sex-linked recessive disorders. A carrier has the defective allele, but ______________. The genotype of a female carrier is ______. Males _______ be carriers for sex-linked traits because their 2nd sex chromosome is the _______! X Y h X X h carriers it does not show X X h H cannot naked Y

2. Sex-Linked Punnett Squares In sex-linked traits, probabilities for male and female offspring must be calculated separately because traits are ________________. 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? inherited differently

Sex-Linked Punnett Squares- 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? Key: __________________ Cross: _________________ Probability of bald daughter = ________ Probability of bald son= ___________

B. Sex-Linked Disorders All of these disorders are sex-linked ___________________. 1. Color Blindness – Inability to differentiate and distinguish ___________________. recessive colors

Left Right Top 25 29 Spots Middle 45 56 Bottom 6 8 Results For Ishihara Test(above) Normal Color Vision Red-Green Color Blind   Left Right Top 25 29 Spots Middle 45 56 Bottom 6 8

B. Sex-Linked Disorders 2. Hemophilia – Missing an enzyme required for normal ____________ - results in _____________________. Treated with blood transfusions, injections of missing factor. blood clotting uncontrolled bleeding

B. Sex-Linked Disorders 3. Duchenne’s Muscular Dystrophy – Symptoms develop at ___________. Muscles ____________________, leading to eventual death. No available __________ or ______. Death usually occurs before adulthood. 3-6 years weaken, break down treatment cure

Examples: A colorblind female marries a man with normal vision. What is the probability of colorblind children? Key: ______________ Cross: ______________ Probability of colorblind daughter: _______ Probability of colorblind son:________

2. A genetics counselor interviews a couple with a family history of hemophilia to evaluate the possibility of offspring with the disorder. The woman does not have hemophilia, but states that her father had the disorder. The man is normal. Key:_____________ Cross: ____________ Son with: _________ daughter with: ______