Question of the Day Feb 18 n Normal

Question of the Day Feb 18 n Normal n A. human zygote cells contain 23 chromosomes n B. 92 chromosomes n C. 46 chromosomes n D. 44 chromosomes

AGENDA Feb 18 n Objective: Describe the value of karyotyping in identifying possible genetic disorders. n 1. Question of the Day n 2. Introduction to Chapter 14 n 3. Karyotyping n 4. Review and Homework

Wilmut’s Technique n Nucleus of an egg cell removed n Fused with a cell from another adult – Requires electric shock n Fused cell begins to divide n Developing embryo placed in the reproductive system of a foster mother n Embryo develops normally

Dolly the Sheep n http: //faculty. coloradomtn. edu/gcornwall/ Starr%20 Concepts%20 Animations%20 and %20 videos/chapter 8/videos_animations/cl oning. html

Chapter 14: The Human Genome

14 -1 Human Heredity n How many chromosomes does an adult human cell contain? n Autosomes – any chromosomes that are not sex chromosomes. n Sex Chromosomes – X and Y chromosomes that determine sex of individual. Normal Individuals represented as n Males 46, XY n Females 46, XX n

Human Cell 22 pairs of homologous chromosomes – called autosomes n 1 pair of sex chromosomes – 23 rd pair n egg, sperm – half the number of chromosomes – egg carries an x, sperm carries a y or x n

ID-ing Chromosomes n Chromosomes are identified by n 1. SIZE n 2. CENTROMERE LOCATION n 3. BANDING PATTERNS

n a picture of chromosomes n homologous chromosomes paired together. n What are they? Numbered 1 -22 in order of size n What is the 23 rd pair? n n What does the size of the chromosome indicate? Karyotype

Question of the DAY n Which Feb 20 statement is not true regarding homologous chromosomes? n A. Specific genes are found at the same locus n B. They have the same size n C. Genes will express identical traits n D. They are joined at the same centromere locations

AGENDA Feb 20 n Objective: Examine the inheritance of genetic disorders through the analysis of pedigrees. n 1. Question of the Day n 2. 14 -1 Notes - Pedigrees n 3. Pedigree Practice Problems n 4. Review and Homework

Alleles Figure 14 -6 n Dominant – Some genetic disorders are expressed through these alleles – Only requires one allele n Recessive – Most genetic disorders are transmitted through these alleles n Codominant – Sickle Cell Disease

AGENDA n n n Feb 23 Objective: Examine the inheritance of genetic disorders through the analysis of pedigrees. 1. Question of the Day 2. 14 -1 Notes - Pedigrees 3. Pedigree Practice Problems 4. Review and Homework – Pedigree Problems – Genetic Disorders Webquest DUE THURSDAY TEST ON FRIDAY

Genes and the Environment n All of our inherited characteristics are governed by our genes. – Many traits are polygenic. n Other factors influence our phenotypes. – Nutrition and Exercise n Average height has increased 10 cm in the last 200 years 3. 93 inches – U. S. and Europe

Pedigree Analysis n rely on family histories and medical records to study humans n pedigree: diagram that follows the inheritance of a single trait through several generations

Pedigrees record and trace the occurrences of traits within a family.

British Royal Family

The Story of Anastasia

AGENDA n Feb 24 Objective: Identify an individual’s blood type through the solving of Punnett Squares. 1. DO NOW – Review Pedigrees n 2. Blood Types and Allele Combinations n 3. Problem Solving n 4. Review and Homework – Problem Solving Packet – Genetic Disorders Webquest DUE THURSDAY n – TEST ON FRIDAY

Blood Group Genes n How many different alleles control blood type? n How is blood type expressed? n How many different blood types are there?

Blood Group Genes n Rh blood groups Positive (+) Negative (-) n Rh+/Rh+ or Rh+/Rh. Rh-/Rhn Blood Type ABA allele and B allele + 2 Rh- alleles n

Blood Type Problems n Solve Punnett Squares to determine the probability of blood types among individuals. n See Blood Types Packet

DO NOW n Explain why males cannot be carriers for sex-linked disorders.

DO NOW ANSWERED n Sex-linked inheritance is directly connected to the X-chromosome. Males only have one Xchromosome and will always express this type of trait/disorder. n Females have two X-chromosomes. Women only carrying one allele for the trait/disorder are carriers. Recessive traits/disorders will not be expressed unless both X-chromosomes carry the allele.

DO NOW n. A Feb 25 mother (type AB blood) and a father (type A blood) have two children. What are the possible genotypes of the children. Show all possible combinations. Solve Punnett Squares to support your answer.

AGENDA Feb 25 n Objective: Solve Punnett Squares to represent the inheritance patterns of sexlinked disorders. n 1. DO NOW n 2. Blood Type Problems Review n 3. Sex-linked Inheritance n 4. Review and Homework

14 -2: Sex-linked Inheritance sex determination – XX female – XY male n sex-linked genes: genes located on the sex chromosomes – almost always on the X chromosome – Y chromosome contains a few genes for male development n

Sex-linked Inheritance males inherit these disorder much more often gets passed from father to daughters, then daughters to their sons n examples are hemophilia, colorblindness, Duchenne’s muscular dystrophy n n

Human Genetic Disorders n autosomal genetic disorders – albinism § recessive allele on chromosome 11 § can’t produce melanin – cystic fibrosis § recessive allele on chromosome 7 § heavy mucus clogs lungs and breathing passageways

DO NOW Feb 19 n Perform the following dihybrid cross. n A homozygous long mane lion that is heterozygous for a loud roar mates with a lioness with a heterozygous long mane and a soft roar. n What are the chances that one of the cubs will have a homozygous long mane and a soft roar? n List all of the possible genotype and phenotype ratios.

AGENDA Feb 19 n Big Question: What is Sex-linked Inheritance? n 1. DO NOW n 2. Review selected HW problems n 3. Chapter 13 Tests n 4. More Genetic Disorders n 5. The Human Genome Project n 6. Review and Homework – Read Section 14 -2 Details of Genetics Disorders

n tay sachs – recessive allele on chromosome 15 – suffer from breakdown of the nervous system n sickle cell disease – recessive allele on chromosome 11 – produces an alternate form of hemoglobin that causes the red blood cells to become a sickle shape – one DNA base changed – Glutamic acid for Valine

Sickle Cell Disease n Allele very prominent in African Americans – Carried by many individuals n Connected to malaria – a parasitic disease that affects red blood cells n Individuals who are heterozygous for sickle cell are resistant to malaria n When body destroys sickled cells, parasite causing malaria also destroyed. – Low oxygen = sickle shape = cells clump together

n PKU: phenylketonuria – recessive allele on chromosome 12 – causes mental retardation n Huntington’s disease – dominant allele on chromosome 4 – lose muscle control and nervous system breaks down

AGENDA n Big Question: What is Sex-linked Inheritance? n 1. DO NOW n 2. Sex-linked Inheritance Section 7 -2 n 3. Pedigree Practice n 4. Closing Thoughts n HAND IN YOUR KARYOTYPE LABS

Chromosome Number Disorders n occurs by nondisjunction: when abnormal number of chromosomes are produced in the sex cells due to them not separating correctly

Turner’s Syndrome either a sperm or an egg is produced without a sex chromosome n XO genotype – O means sex chromosome is missing n sex organs are not fully developed n can not have children n only in females n

Klinefelter Syndrome n have an extra X chromosome – XXY genotype causes mental retardation n can not reproduce n only in males n

Down Syndrome n trisomy 21 – means 3 copies of chromosome #21 n causes heart and circulatory problems, mental retardation, and a weakened immune system

Other Causes of Disorders deletions: can occur from pieces of chromosomes breaking off and getting lost in meiosis n translocation: when pieces of chromosomes break off and become reattached to another n

Prenatal Diagnosis want to detect if unborn child will have a disorder n two ways – amniocentesis: withdraw fluid from sac around fetus – chorionic villus sampling: tissue surrounding fetus is removed and examined n

Special Topics in Human Genetics n n barr body: dense region in the nucleus of most cells in human females condensed turned-off X chromosome not found in males because their one X chromosome is active happens in some tissues and in some cells

AGENDA Feb 21 n Big Question: What is the Human Genome Project? n 1. CHAPTER 14 Problem Solving Test n 2. Complete Chapter 14 -3 Notes n 3. Begin to Study for T 2 Exam

14 -3 Testing for Alleles n DNA probes – specific DNA base sequences that detect the complementary base sequences found in disease causing alleles n Cystic Fibrosis and Tay Sachs are examples that use DNA probes.

DNA Fingerprinting n Repeats are specific sequences of DNA unique to every individual – Do not code for proteins n Repeats cut with restriction enzymes n Gel electrophoresis separates fragments n Labeled with radioactive probes n Forensics, detection of inherited diseases, and paternity cases

DO NOW n Explain Feb 27 how autosomal recessive disorders are passed down from parent to offspring.

DO NOW ANSWERED n Autosomal recessive disorders require both parents to have at least one allele for the disorder. Each parent must then pass this recessive allele on to their child. n The genotype for a child with a recessive disorder of this type is aa, ee, tt, etc. n Both alleles are recessive (lower-case)

AGENDA Feb 27 n Objective: Use genetics tools to determine the inheritance patterns of autosomal and sex-linked disorders. n 1. DO NOW 2. Review for Chapter 14 TESTProblem Solving 3. Problem Solving Review Packet n n – TEST ON Monday March 2

Human Genome Project n Sequencing of all of the genes within an organism. n Human genome sequencing completed in 2003. n Included sequencing of other organisms including E. coli, multiple strains of yeast, the fruit fly, the mosquito, the honey bee, the cow, the dog, the horse, and the rat.

Gene Therapy n Replacement of an absent or faulty gene with a normal working gene.