LECTURE CONNECTIONS 1 | Introduction to Genetics © 2009 W. H. Freeman and Company

Albinism, a genetic condition, arises with high frequency among the Hopi people and occupies a special place in the Hopi culture (1 in 200 people). Albinism is caused by defects in any of the 4 genes that control the synthesis and storage of melanin. Why is albinism so frequent among the Hopi Native Americans? Hopi Native Americans

Introduction to Genetics The importance of genetics: - Albinism in the Hopi Native Americans: genetics altered the occupation, the role in Hopi society, and relations with other members of the tribe. - Genes affect our height, weight, hair color, skin pigmentation, etc. - Genes can influence our susceptibility to many diseases and disorders.

-Genes contribute to our intelligence and personality; -Agriculture; -Domestication of plants and animals; -Pharmaceutical industry: drugs and food additives are synthesized by fungi and bacteria that have been genetically manipulated to make them efficient producers of these substances. Examples: growth hormone, insulin and clotting factor.

-Genetics play a critical role in medicine (sickle-cell anemia); -Gene therapy; -Evolution: is the genetic change taking place through time; -Taxonomy, ecology, and animal behavior are making increasing use of genetic methods; -Developmental Biology: tissues and organs form through the regulated expression of genes.

Genome is a complete set of genetics instructions for any organism. All genomes are encoded in nuclei acids- either DNA or RNA. Genetic variation is the foundation of all evolutionary change and is ultimately the basis of all life as we know it. Genetics: past, present and future. Genome

Transmission genetics: relation between chromosomes and heredity. Molecular genetics: chemical nature of the gene itself. Population genetics: genetic composition of individual members of the same species. Division of Genetics

Model organisms are organisms with characteristics that make them useful for genetics analysis: Model Genetic Organisms

Common characteristics of model organisms: - Short generation time; - Large but manageable number of progeny; - Adaptable to laboratory environment (can be housed and propagated inexpensively).

The history of Genetics Organisms First evidence that people understand hereditary: 10,000-12,000 years ago in the domestication of plants and animals; Greeks (520 B.C.): concept of pangenesis and inheritance of acquired charasteristics.

Aristotle ( B.C.) believed that both males and females made contributions to the offspring. In 1665, Robert Hooke discovered cells and gave scientists the idea of preformationism (all traits would be inherited from only one parent). Blending inheritance: offsprings are a blend. In 1676, Nehemiah Grew reported that plants reproduce sexually by using pollen from the male sex cells. Gregor Mendel discovered the basic principles of hereditary in In 1859, Charles Darwin put forth the theory of evolution through natural selection and recognized that heredity was fundamental for evolution.

Fundamental terms and principles of genetics 2 basic types of cells: - Prokaryotic: lack a nuclear membrane and possess no membrane-bounded cell organelles - Eukaryotic: more complex, possessing a nucleus and membrane-bounded organelles such as chloroplasts and mitochondria The gene is the fundamental unit of heredity Genes come in multiple forms called alleles Genes confer phenotypes and genetic information is the genotype

Genetic information is carried in DNA and RNA Nuclei acids are polymers consisting of repeating units called nucleotides; each nucleotide consists of sugar, a phosphate, and a nitrogenous base (DNA: A, C, G and T; RNA: A, C, G and U). Genes are located in chromosomes Chromosomes separate through the processes of mitosis and meiosis Genetic information is transferred from DNA to RNA to protein Mutations are permanent Some traits are affected by multiple factors Evolution is genetic change