Chapter 10 Gene control of proteins as the gene product

First, the question of what do genes do.

Early work of George Beadle (corn geneticist, moved to Drosophila (in Morgan's lab, and then to Neurospora.

Beadle and Tatum picture..(not on web)... BeadleTatum-1958-1.GIF

Work on transplanting tissue in Drosophila: BeadleDrosophila.gif

Nobel lecture by Beadle at:   http://www.nobel.se/medicine/laureates/1958/beadle-lecture.pdf

one gene one enzyme hypothesis; Garrod (Inborn Errors of Metabolism), Beadle and Tatum

Neurospora life cycle...somatic nuclei haploid... neurospora1.GIF

Historical perspective: Perkins, D. D. (1992). "Neurospora: the organism behind the molecular revolution." Genetics 130(4): 687-701. "In Japan, Neurospora made a dramatic apearance following the great Tokyo earthquake and fire of 1923"

Two types of media: Complete and minimal.....NeurosporaMedia.GIF

protocol for experiments...BeadleTatum1.GIF

BeadleTatum2.GIF

Results... Table 10.1 and Figure 10.3

For arginine and intermediate compounds ...... Neurospora.gif

Location of mutations and pathways Figure 10.4 ....08x3.gif

 

idea: One gene one enzyme; has undergone several modifications, as one gene one polypeptide, one gene one function, one gene more than one polypeptide.

"While it is important to identify every gene, it is actually the proteins that do the work of carrying out the information coded within the genes.  Since one gene can code for more than one protein, there are many more proteins than there are genes.  For example, humans have about 30,000 genes but about 250,000 proteins!  This means that the protein maps will be much larger and more complex than the corresponding gene maps."

Work of Garrod...Inborn errors of metabolism; work on four traits: albinism, alkaptonuria, cyctinuria, pentosuria

picture..(not on web)...Garrod

As Fig 10.1.... GarrodAlkaptonuria.gif

MORE ....1902 paper via web..http://www.esp.org/foundations/genetics/classical/ag-02.pdf

 

We will use hemoglobin as a model for various aspects of molecular genetics.

Information is provided in the form of the hemoglobin sheet, handed out today.

It is also available on the web via: ... betaglobin.pdf

Reference to the web site of M. Tevfik Dorak.  I have used material from this site before for my own research but now think some of you may be interested in browsing through it.     Dorak's site     For example, he has a page called  Possible Misunderstandings and Misconcepts in Genetics.  You might be interested ...http://dorakmt.tripod.com/genetics/misund.html

protein structure (discussed again in chapter 12)

Overview

List of amino acids..page 250; and on hemoglobin sheet

Degrees of complexity (page 251 and Figure 12.4 in your text)

Primary structure

Secondary structure

Tertiary structure

Quaternary structure

 

12 November 2004

Continue with chapter 

Proteins and mutations

Example, alpha and beta globin: .. AminoAcidSeqs.GIF

Sickle cell anemia..

Hb S mutation and pleiotrophic effects..... Pleiotrophy.gif

Gel electrophoresis (not on web).   ../../Other%20Graphics/Electrophoresis.gif      

First seven amino acids ... Figure 10.8 ..    ../../Other%20Graphics/07.gif 

see homoglobin sheet   picture 2 ......  ../HemoglobinPicture2.gif

protein function; human diseases

see Table 10.2 for list of inborn errors of metabolism

On PKU,  phenylketonuria

    For PKU: excellent presentation in form of text and visual/verbal presentation of two days of lectures: http://consensus.nih.gov/cons/113/113_intro.htm of importance: that which was thought to be a simple trait has turned out to be very complex (surprised?). Some of this complexity will be seen at the end of the course. .... For PKU please read description in the text...... fits into the ideas presented by Garrod a long time ago.

To chapter 11... Chapter11.html