John R. Hoffman is a Professor of Biology, public speaker and a scientist examining the recovery of the nervous system after injury. Since 2006 he has written several unpublished manuscripts and he is currently working on the first Nathaniel Smythe novel and short story collection. He spends his spare time with his family and running.

27 Basic concepts of DNA and Heredity

Objectives

By the end of this lecture, the student will be able to:

  1. Describe the basic structure of DNA and chromosomes.
  2. Explain how the message of DNA is coded in a gene.
  3. Describe how genetic information is passed from parent to offspring.

Part 1. Basic Structure of DNA

This is the first of a three-part lecture on the basic concepts of DNA. The handout for this presentation can be downloaded and printed.

Part 2. Genetic Properties of DNA

This is the second in the series of lectures on the basics concepts of DNA focusing on the genetic message coded within the DNA molecule. The handout for this presentation can be downloaded and printed.

Part 3. DNA and Heredity

This is the third in the series of lectures on the basic concepts of DNA and examines the passage of DNA and traits from parent to offspring. The handout for this presentation can be downloaded and printed.

Readings:

The New Genetics (2010). NIH Publication 10-662. National Institute of General Medical Sciences. National Institutes of Health. Chapter 1. How Genes Work, pp. 4 – 23

Help Me Understand Genetics: Cells and DNA (2012). National Library of Medicine, National Institutes of Health. Reprinted from Genetics Home Reference (http://ghr.nlm.nih.gov/)

Assignment: Roll the Dice

For many basic genetic traits, Genetic Counselors are able to use simple probability to determine the likelihood of having a child with a specific trait. Many recessive genetic medical conditions can also be examined in the same way when it is known that one or both of the parents may be a carrier for the specific trait.

In your discussion group: Discuss whether or not it is ethical for parents that are carrying the allele for a debilitating genetic condition to attempt to have a child. Assume that the parents know that there is a 25% (1 out of 4) chance of having a child with the genetic disorder and a 75% (3 out of 4) chance of having a healthy child. Do the ethical arguments change if the likelihood of having a healthy child increases or decreases?

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