CHAPTER 22:

GENOMICS

By:Bryan VinzantKimberly BlackMatthew HehemannRavon Williams

FROM GENETICS TO GENOMICS

Genomics : is the study of Genomes. Genomes : “refer to all the DNA in a haploid

set of chromosomes, including non- protien-encodeing sequences.” (Lewis 430)

Positional Cloning: A technique that discovers genes

Genetic Maps: isolate specific genes, their locations, and their function. The following are examples of the levels of genetic mapping: Cytogenetic Map: distinguishes DNA

sequences 5,000 kb apart Linkage Map: distinguishes genes hundreds

of kb apart Physical Map: distinguishes genes tens of

kb apart Physical Map: distinguishes down to the

nucleotide bases

Key Terms Human Genetic Map(Watson)

Genetics has led to the creation of the field of Genomics. Those in this field use genetic mapping to study ways to predict, diagnose, treat, and prevent genetic illnesses.

As technology has advanced we have narrowed down from the Cytogenetic map, to the Linkage map developed in the fifties all the way to the Physical map and Sequence map which actually breaks down to the nucleoid bases. This has allowed us to isolate a disease causing gene in a matter of weeks.

Researchers used positional cloning to help indentify markers that discovered the genes for such diseases as Duchenne muscular dystrophy, cystic fibrosis, and Huntington's disease.

Genomics has evolved from Gregor Mendel's pea plant experiments, through H. Winklers studies in the 1920’s when he coined “Genome.” From there we include linkage maps dating back to the 1950’s through to the 1990’s the technology developed to the Human Genome Project.

HTT otherwise known as the Huntington Gene

U.S. National Library of Medicine

THE HUMAN GENOME PROJECT AND BEYOND

Since Watson and Crick determined the structure of

DNA scientists have had thoughts of sequencing

genomes. In 1984 public discussion

of sequencing the human genome began

In 1990 the Human Genome Project Officially commenced

In 2003 the finished version of the human genome sequence was announced

Logo courtesy the U.S. Department of Energy Human Genome Program http://www.ornl.gov/hgmis/home.shtml

The Sanger technique, still used for sequencing DNA today was developed in 1977 by Frederick Sanger

The technique works by generating a series of DNA fragments of progressively longer length that are identical to the sequence of interest

The end bases of the fragments are then labeled with a fluorescent tag

Once overlapping areas are aligned a sequence is derived from the end tags

Below are the graphical representations of two different approaches used in unraveling the human

genome Celera Genomics used a whole genome approach

The International Human Genome Mapping Consortium

approached a single chromosome at a time

COMPARITIVE GENOMICS• “The graphs on the next slide indicate the

similarity between the human genome and those of the chimpanzee and the mouse as they are mapped to identical locations in the human genome. Since the chimpanzee genome is closer in evolutionary time to the human genome, the chimp chromosomes map very closely to human chromosomes. The mouse genome is more distant in evolutionary time from the human Genome.’

Hiram Clawson and Kate Rosenbloom 09 June 2006

COMPARING HUMAN, CHIMP, AND MOUSE GENOMES

CHIMP MOUSE

Chromosome numbering is purely arbitrary, based upon early microscopic estimates of chromosome length.

The chimpanzee genome has 23 numbered chromosomes, the human genome has 22 numbered chromosomes, the mouse genome has 19 numbered chromosomes.

DO YOU WANT YOUR GENOME SEQUENCED?

•This century genetics has gone from an obscure science to a well known field with many potential practical applications (A few are listed in the illustration).•Scientists are now attempting to establish a “healthy cohort,” a collection of extraordinarily healthy people. With the intent of analyzing their shared gene variations that may be the cause of their extraordinary health. “It is hoped that this project could lead to new treatments based on how protective gene variants function and interact.” (Lewis, 2009)

GENETIC AWARENESS Health and life insurance costs could be individualized

based on which disease and susceptibility gene variants are present in your body “This could be a pro or a con depending on your individual results, as it could mean either a cheaper rate or a very expensive rate and/or denial of coverage...” It may become possible to check your children for the probabilities of occurrence for different genetic conditions, allowing for increased awareness.

Whether or not knowing you risks for certain diseases encourages avoidance of high risk factors is still a matter of much debate. Currently Scripps Translational Science Institute is running a 20 year test with their 10,000 employees in an effort to answer this question. (Goetz, 2008)

BIBLIOGRAPHYBalwin, M (2007, July 12) Cartoonstock Retrieved July 09, 2009, Modified by Hehemann, Mathew on

retrieval date http://www.cartoonstock.com/cartoonviewasp?search=site&catref=mban2136&MA_Category=&ANDkeyword=fortune&ORkeyword=&TITLEkeyword=&NEGATIVEkeyword=.

Clawson, Hiram and Rosenbloom, 09 June 2006; Genome Browser at UC Santa. Retrieved on June 12, 2009 from http://www.cbse.ucsc.edu/research/comp_genomics/human_chimp_mouse.

Goetz, T. (2008, October 9). What Good Is Your Genome, Really? Wired magazine. Retrieved July 13, 2009, from http://www.wired.com/wiredscience/2008/10/what-good-is-yo/.com.

Huntington Gene June 26 2009 26. Retrieved July 10, 2009, from U.S. National Library of Medicine http://ghr.nlm.nih.gov

Lewis, R. (2008). Human Genetics (Vol. Eighth Edition). New York: McGraw-Hill.

U.S. Department of Energy Human Genome Program. (2008). Human Genome Project Information. Retrieved on 7/11/09, http://www.ornl.gov/hgmis/home.shtml

Watson, J. (1990). The Human Genome Project: Past, Present, and Future.Retrieved July 9, 2009, from University of Illinois: www.life.illinois.edu