HUMAN GENETICS CONCEPTS AND APPLICATIONS EIGHTH EDITION OVERVIEW OF GENETICS Chapter 1

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1-2 Superboy Case Study  Description/symptoms of disorder-  What causes superboy syndrome?  What is the function of myostatin?  Bioengineering-  What are some possible ways myostatin could be used?  Do you see any disadvantages?  Bioethics- definition  field of study of the ethical problems arising from scientific advances, esp. in biology and medicine. –organ transplants, genetic engineering, terminally ill care; nonhuman issues- environment, animal testing.  Bioethical issues?  Bioethics Resource Site- NIHBioethics Resource Site- NIH

Genetics What is Genetics? Why study Genetics? Branch of Biology Study of inherited traits and their variations. What is included in this field?

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Levels of Genetics Genes  units of heredity  composed of DNA (Deoxyribonucleic Acid)-  the code that directs cells to manufacture proteins.  Proteins control characteristics  Most Human genetics-are multifactorial- result of genes and the environment. Red hair, fair skin, freckles- melanocortin 1 receptor- protein that controls pigments in skin- Found in 80% individuals.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1-5 The Genome  Complete set of genetic information for an organism  Includes:  All of the genes present in an organism Includes protein encoding genes and non-encoding genes.  Human genome sequenced in ,600 genes OMIM- Online Mendelian Inheritance in Man- online database for disorders or traits Research continues in what the information means and gene interaction. Rapidly expanding area of biology.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1-6 Levels of Genetics DNA- genes-chromosomes-genomes, individuals, families, populations

Deoxyribonucleic Acid (DNA) Polymer of nucleotides (monomer) Double stranded helix Remains in the nucleus. Deoxyribonucleotide components: Phosphate Sugar: Deoxyribose Base- 4 different bases Guanine GAdenine A Thymine TCytosine C Nucleotides are named for the base they contain. The sequence of the bases code for the amino acid sequence in a protein

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1-8 The nucleotide chains are anti-parallel. Read 5` to 3` direction

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1-9 Ribonucleic Acid (RNA)  Polymer  Single stranded  Chain of ribonucleotides (monomer)  Ribonucleotides components: (3) Phosphate Sugar: Ribose Base: Guanine GAdenine A UracilUCytosine C  Several types- mRNA, tRNA, rRNA  Uses information in DNA to make proteins

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Genome  Proteomics – which genes are expressed in cell types  Only 1.5% of the DNA in the human genome encodes protein  Rest includes highly repeated sequences with unknown functions  Includes about 24,000 protein encoding genes  Cataloged in database  Mendelian Inheritance in Man (MIM)

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Alleles-  Alleles are variants of genes  They form by mutation  Mutations in sperm or egg cells are passed on to the next generation  May be positive, negative, or neutral  Examples -

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Variations  Polymorphisms are variations in the DNA sequence that occur in at least 1% of the population  Single nucleotide polymorphisms (SNPs) are single base sites that differ among individuals and are important as markers

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Chromosomes  Composed of DNA and protein  Found in the nucleus of the cell  Human cells have 46 chromosomes (23 pairs)  # autosomes  #23- sex chromosomes X and Y  Females have two X chromosomes  Males have one X and a Y

A Karyotype chart of the chromosomes organized by size (#1-longest) determine sex, abnormal chromosome number, or missing sections of chromosomes can NOT view individual genes.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Cells  All cells with a nucleus in the body contain the same genetic information  Differentiation causes cells to differ in appearance and function. This is controlled by variation in gene expression.  Stem cells are less specialized and can become many different cell types

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Individual  The genotype of an individual is the alleles they carry.  The phenotype is the visible trait or physical appearance.  Dominant alleles are expressed if the individual carries one or two copies of the allele.  Recessive alleles are only expressed if the individual carries two copies of the allele.

The Family Inheritance of traits can be observed in families. A pedigree indicates the structure of a family schematically. Figure 1.2

Population- Is a group of interbreeding individuals (members of the same species in a specific area) The gene pool is the sum of the alleles in a population Evolution is the changing allele frequencies in populations over time.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Evolution  Comparison of DNA sequences indicates the amount of similarity between two species.  98% of human DNA sequences are shared with chimpanzees.  Humans share genes with mice, fish, fruit flies, yeast, and bacteria.

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Most Genes Do Not Function Alone Mendelian traits are determined by a single gene Most traits are multifactorial and not controlled by a single gene. They are influenced by more than one gene and the environment Some illnesses may occur in different forms: Mendelian, multifactorial, and non- inherited

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Genes and Disease Risk  Mendelian traits have simple inheritance- 1 gene  Multifactorial traits more complicated  BRCA1 gene and breast cancer Ethnic influences as well as environmental  Knowing risk can help us make good choices

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Applications of Genetics Forensics Identifying victims, DNA at crime scenes, overturning convictions, adoptions Rewriting history Thomas Jefferson offspring, the Jewish Lemba Common ancestry

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Health care Legislation HIPAA (Health Insurance Portability and Accountability Act) of federal law Title I of HIPAA protects health insurance coverage for workers/their families when change/lose jobs.health insurance Title II of HIPAA, known as the Administrative Simplification (AS) provisions, establishment of national standards for electronic health care transactions and national identifiers for providers, health insurance plans, and employerselectronic health care requires employers to protect employee medical records as confidential. provides rights and protections for participants and beneficiaries in group health plans. prohibit discrimination against employees and dependents based on their health status

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display GINA  GINA- 2000, 2008 May — President, George W. Bush - Law-Genetic Information Nondiscrimination Act (GINA) that will protect Americans against discrimination based on their genetic information when it comes to health insurance and employment. Importance of this legislation? Because of this legislation, Americans will be free to undergo genetic testing for diseases such as cancer, heart disease, diabetes, and Alzheimer’s without fearing for their job or health insurance,” said House speaker Nancy Pelosi

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Other related issues  Prediction of disease  Genetic testing, concerns over privacy  Development of treatments  Family planning

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Applications of Genetics Agriculture- field of genetics arose from agriculture  Biotechnology-  use of organisms to produce goods  Crop and animal breeding  Genetically modified foods-  Altered to have new genes or over or under express their own genes.  Transgenic- genes from another species  “golden rice”  Advantages  disadvantages

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Applications of Genetics  Ecology  Metagenomics – new field  sequencing DNA from a habitat  examples Sargasso Sea, air samples, human body-mouth, digestive tract  Global perspective and human health  Malaria and mosquitos.