Introduction
1. Genetics is a branch of biology concerned with inherited traits and their variation.
2. Genes are the unit of heredity that instruct cells how to manufacture proteins.
3. Genes are composed of DNA. The complete set of genetic information is called the genome.
4. Genomics is the field of biology that studies gene interactions.

1.1 Genetic Testing
1. DNA from an individual can be placed on a DNA chip and analyzed using a microarray.
2. Results from microarray analyses are interpreted by genetic counselors.
3. Special microarrays, called expression panels, can study the expression of genes in relation to a specific tissue or disease.

1.2 Levels of Genetics
1. Genes consist of sequences of DNA. DNA is made of four basic building blocks – adenine, guanine, cytosine and adenine.
2. RNA uses information from selected DNA sequences to build proteins.
3. The study of proteins is called proteomics.
4. RNA may also control protein manufacture by a process called RNA interference.
5. Genes can exist in more than one form, called alleles. Mutation causes the formation of alleles by changing the DNA sequence.
6. A polymorphism is a particular sequence of DNA that varies in one percent or more of the population.Single nucleotide polymorphisms are single base pair sites that differ among individuals.
7. Chromosomes consist of genes and associated proteins.
8. The human genome consists of 22 pairs of autosomes and one pair of sex chromosomes.
9. A karyotype is the photographic catalog of the human chromosomes.
10. Specialized cells and tissues arise by differentiation from the stem cells of the early embryo.
11. Stem cells are unspecialized cells that maintain a reserve supply of cells to repair damage and grow.
12. The genotype represents the alleles present in an individual, the phenotype is the expressed allele for a trait.
13. Dominant alleles have an effect when only one copy is present, recessive alleles require two copies in an individual to be expressed.
14. Pedigree diagrams enable recessive and dominant traits to be followed through multiple generations of a family.
15. A gene pool is the collection of alleles in a population.
16. Comparative genomics is leading to a more detailed and subtle understanding of evolutionary relationships among species.

1.3 Most Genes Do Not Function Alone
1. Mendelian traits are determined by single genes.
2. Multifactorial traits are determined by multiple genes and environmental effects.
3. Environmental factors may influence gene expression.
4. Modified genetic risk examines the influence of single genes, environment, and family background to develop predictions of inherited disease
5. Genetic determinism is the point of view that the environment has little effect on gene expression.

1.4 Statistics Represent Risks
1. Genetic counselors apply knowledge of mode of inheritance and pedigrees to determine probability of inheriting a particular trait or condition.
2. The risk of inheriting a trait or condition is expressed as absolute risk or relative risk.
3. Risk figures are based on population level observations (empiric), Mendel's laws, or are "modified" to account for single genes as well as environmental and family background information.

1.5 Applications of Genetics
1. Genetic tools are used in diverse areas such as forensics, establishing paternity, agriculture, and health care.

Establishing Identity
1. DNA profiling can exclude an individual from being biologically related to someone else or from having committed a crime.
2. DNA databases have been established in many countries and states, although there are ethical considerations regarding their use.
3. DNA profiling can be used to analyze family relationships, or the origins of groups of people in diverse areas of the planet.

Health Care
1. Inherited diseases differ from infectious diseases in three distinct ways. First, it is possible to predict the recurrence of a single-gene disease. Second, the risk of developing symptoms can be predicted. Third, genetic diseases may be more prevalent in one population than another.
2. After identifying underlying genetic abnormalities (mutations), gene therapy may be used to treat and possibly prevent certain genetic disorders.

Agriculture
1. Agriculture, both traditional and biotechnological, applies genetic principles.
2. Biotechnology is the use of organisms to produce goods.
3. Traditional agriculture involves controlled breeding to select new combinations of inherited traits.
4. Genetically modified (GM) foods have genes introduced from the genomes of other organisms.

Ecology
1. Metagenomics is the application of genomics to all members of a habitat to understand how organisms and species interact.

Genetics from a Global Perspective
1. Genetics has applications in diverse areas.
2. Genetics has spawned new technologies and possibilities, including genome-based individualized health care.
3. Human genome information has tremendous potential but must be carefully managed.