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Unformatted text preview: 0 Genetics: From Genes to Genomes
2nd & 3rd Editions
Hartwell Hood Goldberg Reynolds Silver Veres Chapter 1
1 Genetics 0 2 Genetics
The Study of Biological Information 0 3 Chapter Outline 0 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, since they are the most interesting!
4 Information in DNA generates diversity 0 Fig. 1.1a Process of evolution has taken ~4 billion years to generate organisms seen today Four bases G (guanine), A (adenine), T (thymine), and C (cytosine) are the nucleotide building blocks of DNA DNA is a double stranded helix composed of AT and GC complementary bases Order of nucleotide sequences determine which proteins are synthesized, as well as when and where the synthesis occurs
5 Genetic Information is Digital 0 Fig. 1.3 Although DNA is 3D, information within the molecule is 1D and "digital" The sequence of bases in DNA can be read by DNA sequencers, stored in computers, and synthesized by DNA synthesizers 6 Genes are sequences of DNA that encode proteins 0 Fig. 1.2 GENE: DNA region that encodes proteins EXON: coding region of DNA 7 DNA resides in within cells packaged as units called chromosomes 0 Fig. 1.4 The entire collection of chromosomes in each cell of an organism is called a genome Humans have 24 chromosomes (why not 23?) The human genome has about 3 x 10 base pairs and 40,000 60,000 genes (underestimate) 8 0 9 Amino acids have a basic amino group (NH) and an acidic carboxyl group (COOH) Alanine has a relatively simple CH side chain Tyrosine has a more complex aromatic side chain Biological function emerges primarily from proteins 0 Figure 1.5a 10 A comparison of equivalent chains of two digestive proteins 0 Figure 1.5b 11 Proteins are polymers of amino acids 0 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 12 The diversity of protein structure generates extraordinary diversity 0 Fig. 1.5c 13 Proteins interact with DNA and other proteins 0 Biological systems function as complex interactive networks of proteins and DNA that interact with one another Fig. 1.6 14 All living things are closely related 0 RNA was probably the first information processing molecule, but RNA is unstable RNA is composed of four bases: guanine (G), adenine (A), cytosine (C), and uracil (U) Fig. 1.7a 15 All living organisms use the same arbitrary codes for RNA, DNA, and protein 0 Fig. 1.7b 16 Many genes have similar functions in very different organisms 0 Fig. 1.8 17 Convergent Evolution 0 The independent development of similar structures or capabilities in organisms that are not directly related 18 Relatedness among organisms is important for the study of human genes 0 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. 19 Modular construction of genomes has allowed rapid evolution of complexity 0 Gene families arise from primordial genes through duplication and rearrangements Duplication and divergence of new genes can generate genes with new functions We'll examine traits that are controlled by multiple genes and single genes (for example...)
20 Widow's Peak Hairline 0 Yes No
21 Ear Lobes 0 Attached Free
22 Tongue Rolling 0 Roller Non-Roller
23 Middigital Hair 0 Hairy Non-Hairy
24 X So, what do these traits mean? 0 Nothing really... 25 The process of duplication and divergence 0 Fig. 1.10 26 Duplication and divergence has made rapid evolution possible 0 27 Rapid change in regulatory networks specify how genes behave. Fig. 1.9 28 Genetic techniques permit the dissection of complexity
0 Genes can be identified and inactivated one at a time using genetic techniques Dissection of genomes genebygene 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 29 Genome sequencing projects are a step in understanding the complexity of genomes
30 New technological tools facilitate the dissection of genomes and integration of information
0 Fig. 1.13
31 Focus on human genetics 0 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
32 Genetics Predictive and Preventative Medicine 0 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 33 Social issues and genetics 0 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?
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