Heredity

Heredity

After studying this chapter, the reader should be able to:

1. Identify what was achieved by the Human Genome Project.

2. Define the terms genes, chromosomes, autosomes, alleles, and homozygous.

3. Distinguish between dominant and recessive alleles.

4. List the three events that occur as part of genetic variation.

5. Explain the concept of multiple allele inheritance using the ABO blood group.

6. Identify factors that may influence or override gene expression.

7. Contrast Prader–Willi syndrome and Angelman’s syndrome.

8. Explain why mitochondrial (extranuclear) genes are usually transmitted from the mother to her offspring.

9. Identify the newer procedures that will likely replace amniocentesis and chorionic villus sampling.

10. Give examples of how gene therapy may be used.

Overview

The science of genetics is the study of heredity. In the mid-1800s, Gregor Mendel was the first scientist to propose basic principles of heredity. Today’s genet-icists are able to engineer and manipulate human genes in order to examine the ways in which they are expressed. The Human Genome Project was undertaken to determine the actual human DNA sequence. As the field of genetic screening develops, many future medical outcomes as yet not even imag-ined will be possible. Already, the use of the human genome is allowing for drugs to be developed that are more effective in treating diseases and even curing them.