Lecture 1

Cummings 1

GENETICS AS A HUMAN ENDEAVOR

I. Issues to be addressed

II. Early studies of genetics

Terms

1. What are genes and what do they do?

2. What are the rules that govern transmission of genes to offspring?

3. What is the genetic basis for sex determination?

4. How can genes be studied for prediction of the appearance of inherited diseases?

5. What role do genes play in risk of cancer?

6. To what extent does heredity influence behavioral differences?

7. How are genes involved in organ transplantation?

8. What is gene therapy? How is it done?

9. How are genes transferred from one species to another?

10. How are sheep, cattle, mice (and humans) cloned?

11. How do environmental agents (radiation, chemicals) cause genetic damage?

12. How is DNA used to establish biological relationships among related persons and to identify criminals?

13. How are genes and DNA used to trace evolutionary pathways?

14. How are genes and DNA used to establish the evolutionary relationships among contemporary human populations?

15. What do genes tell us about the genetic diversity among populations and individuals?

A. Pre-Mendelian era

1. The theory of pangenesis (Darwin) proposed that all parts of the body contribute to the formation of eggs and sperm. This included the idea of inheritance of acquired traits.

2. There were contradictory ideas on whether development consisted of growth of a fully preformed human (preformation) or development of new complex structures from simple structures (epigenesis).

B. Pre-Mendelian scientific studies of heredity were based primarily on complex traits.

1. Francis Galton developed the early mathematics necessary to describe variation and correlation, both important tools in the study of complex traits (and in all areas that use statistics).

2. Complex inherited traits are currently viewed as the sum of actions of many genes.

C. The rules of Mendel, first published in 1865, were "rediscovered" in 1900 and are the foundation of modern understanding of heredity.

D. Evolution and adaptation

1. Lamarck proposed that acquired traits could be passed on to offspring.

2. Darwin also believed that acquired traits could be passed to offspring but thought a more important factor in adaptation is natural selection.

3. Adaptation, if extensive, can generate new species and is a major mechanism in evolution. This was contrary to the prevailing idea prior to Darwin that species are constant.

E. Genetics and eugenics

1. Genetics - the study of heredity - became a major scientific discipline with the rediscovery of Mendel's work in 1900.

2. Eugenics - the improvement of the human species by selective breeding - is a social and political idea that became popular in Europe and America in the late 19th century.

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