1. The Study of Biological Information
Genetics
The Study of Biological
Information

2. Chapter Outline
DNA molecules encode the biological information fundamental to all life forms
Proteins are the primary unit of biological function
Regulatory networks specify the behavior of genes
All living forms are closely related
Genomes are modular, allowing rapid evolution
Genetic techniques permit dissection of biological complexity
Focus of this course is on human genetics

3. Information in DNA generates diversity
Four bases – G (guanine), A (adenine), T (thymine), and C (cytosine) are the nucleotide building block of DNA
DNA is a double stranded helix composed of A-T and G-C complementary bases
Order of nucleotide sequences determine which proteins are synthesized, as well as when and where they the synthesis occurs.
Figure 1.1a
Fig. 1.1a

4. Genetic Information is Digital
The sequence of bases in DNA can be read by DNA sequencers, stored in computers, and synthesized by DNA synthesizers
Figure 1.3
Fig. 1.3

5. Genes are sequences of DNA that encode proteins
Figure 1.2
Fig. 1.2

6. DNA resides in within cells packaged as units called chromosomes
The entire collection of chromosomes in each cell of an organism is called a genome
Humans have 24 chromosomes
The human genome has about 3.2 x 109 base pairs and 30,000 – 35,000 genes
Figure 1.4
Fig. 1.4

7. Biological function emerges primarily from proteins
Figure 1.5a
Figure 1.5a

8. Proteins are polymers of amino acids
Proteins have three dimensional structures
Information in DNA dictates the sequence of its amino acids
There are 20 different amino acids
The order of amino acids determines the type of protein and its structure

9. The diversity of protein structure generates extraordinary diversity
Figure 1.5b
Fig. 1.5b

10. Proteins interact with DNA and other proteins
Biological systems function as complex interactive networks of proteins and DNA that interact with one another
Figure 1.6
Fig. 1.6

11. All living things are closely related
RNA was probably the first information-processing molecule
RNA is composed of four bases: guanine (g), adenine (a), thymine (t), and uracil (u)
Figure 1.7a
Fig. 1.7a

12. All living organisms use the same arbitrary codes for RNA, DNA, and protein
Figure 1.7b
Fig. 1.7b

13. Many genes have similar functions in very different organisms
Figure 1.8
Fig. 1.8

14. Relatedness among organisms is important for the study of human genes
Studies of genetics in model organisms help us understand how genes work in humans
Some model organisms include bacteria, yeast, roundworms, fruit flies, and mice.
Model organisms may have simpler biological networks and can be manipulated experimentally.

15. Modular construction of genomes has allowed rapid evolution of complexity
Gene families arise from primordial genes through duplication and rearrangements
Duplication and divergence of new genes can generate genes with new functions

16. The process of duplication and divergence
Figure 1.10
Fig. 1.10

17. Duplication and divergence has made rapid evolution possible

18. Rapid change in regulatory networks specify how genes behave
Figure 1.9
Fig. 1.9

19. Genetic techniques permit the dissection of complexity
Genes can be identified and inactivated one at a time using genetic techniques
Dissection of genomes gene-by-gene unravels the complexity of biological systems
The challenge for modern biology lies in understanding how the multitude of networks of genes and higher level systems interact to produce complex systems.

20. Genome sequencing projects are a step in understanding the complexity of genomes
Figure 1.12
Fig.1.12

21. New technological tools facilitate the dissection of genomes and integration of information
DNA chips detect the expression of thousands of genes in response to environmental changes
Figure 1.13c
Fig. 1.13c

22. Focus on human genetic
Genetics is a field of science that will have an enormous impact on society
Our understanding of biological complexity using genetic approaches is proceeding at a very rapid pace
Recent technological advances have shifted the focus of genetics from analysis of single genes and proteins to entire networks – the Systems Approach

23. Genetics Predictive and Preventative Medicine
Discovery of genes with variations that cause or predispose one to disease will continue at a rapid pace.
Gene therapy
Diagnostics
Therapeutic drugs to block or reverse effects of mutant genes
Detection of disease and treatment before onset may increase life span significantly

24. Social issues and genetics
Should an individual’s genetic profiles be freely available to insurance companies, employers, government?
Should our government regulate the use of genetic and genomic information to reflect societies social values?
Is it okay to permanently alter genes in humans for medical or social reasons?