A Perspective on Human Genetics

Chapter 1

Genetics is the Key to Biology

!  Genetics •  The scientific study of heredity – how traits are

passed from one generation to the next •  Includes the study of how genes function in cells

!  Understanding genetics is essential to understanding life!

What are Genes and How do they Work?

DNA (Deoxyribonucleic Acid)

! Helical molecule: Two stands of nucleotides •  Primary carrier of

genetic information •  4 Letters in the genetic

alphabet: A, C, G and T

From DNA to Protein

!  A gene is transcribed into RNA and then translated into protein

!  A protein has a three dimensional shape

Gregor Mendel: The Father of Genetics

!  He discovered how genes are transmitted from parents to offspring

!  He published his results 150 years ago, long before we knew about chromosomes, genes and DNA

Chromosomes come in pairs in humans

!  Genes are parts of chromosomes •  Meiosis separates chromosomes during formation

of egg and sperm

How Do We Study Genes?

!  Cytogenetics - Karyotyping

!  Molecular Genetics - Recombinant DNA, Genomics, RFLP Analysis, Gene Therapy

!  Transmission Genetics - Pedigree analysis, Family Traits

!  Population genetics - Databases, Genetic Distribution

Transmission Genetics: Pedigree Analysis

!  Follows the passing of Traits within a family

Cytogenetics - Karyotype

!  Chromosomes arranged by size, shape, and other characteristics

Molecular Genetics

Analyzing DNA to identify the cause of disorders and cancer

Changing genes, Altering Phenotypes for Food, Medicine,Health

Has Genetics Affected Social Policy and Law?

!  Eugenics was an influential force in American life from 1905 through 1933 •  Restricted immigration to “superior” peoples

video

Eugenics and Laws Requiring Sterilization

!  Carrie Buck and more than 60,000 others in the United States were sterilized for “appearing” genetically, intellectually, or morally �inferior�

The Human Genome Project

!  Analysis of groups of single nucleotide polymorphisms (haplotypes) show differences among individuals at the molecular level

SNP

SNP

SNP

SNP

Person 1

Person 2

Haplotype 1

Haplotype 2

Person 3 Haplotype 3

Person 4 Haplotype 4

New Genetic Technologies

!  A DNA microarray can (or DNA chip) be used to determine genetic disorders an individual has or will develop

In Vitro Fertilization

!  Fertilization outside the body !  Genetic testing can be done at the early embryonic

stage to determine whether the embryo has inherited defective genes

What Impact is Genetics Having Now? !  Biotechnology

•  Commercial uses for genes

!  Human Genome Project •  Mapping all human genes •  Ethical use of genetic information

!  Health Care •  Gene Therapy, Karyotyping

!  Genetic Testing •  DNA Microarrays

!  Social Policy and Law •  Immigration and Reproductive Laws