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Subject: Gene mapping: origin, development, status, etc.

From: PHirth <PHirth_at_aol.com>
Date: Wed, 4 Mar 1998 18:10:17 EST
To: angenmap_at_iastate.edu
Subject: Homework

When did gene mapping get dicovered? by whom? how?
What was thought about it?
What important people played a part in this discovery? How were they a part?
What was it used for then?
From: "James Womack" <jwomack_at_CVM.TAMU.EDU>
Date: Thu, 05 Mar 1998 10:12:54 -0600
To: angenmap_at_iastate.edu
Subject: Re: Homework

For PHirth (homework).
The first gene map was published by Alfred H. Sturtevant in 1913.  The map
included six genes for such things as eye color, wing shape, and body size
and color on the x-chromosome of the fruit fly, Drosophila melanogaster.  
Drosophila was one of very few animal species that could be manipulated
for genetic analysis at the time and remains a very important organism for
genetic research today.  The map was based on the fact that these six
genes did not segregate independently of each other in meiosis (cell
division leading to the production of sperm and eggs -eggs in this case). 
They behaved as if they were on the same chromosome (or genetically
"linked"), a fact that Sturtevant might not have recognized except for the
observation of chromosomes by a number of microscopists in the late 1800s
and Walter Sutton's recognition in 1903 that Mendel's rules of inheritance
were related to chromosomal distribution during meiosis.  Thomas Hunt
Morgan received the 1933 Nobel Prize (the first for a geneticist) for his
expansion and proof of Sutton's ideas and for first demonstrating a gene
was located on the x-chromosome of Drosophila.  Morgan was Sturtevant's
advisor: I forgot to mention that Sturtevant began this work as an
undergraduate student at Columbia University.  So, back to the map; the
linked genes were ordered on the x-chromosome based on the frequency with
which they recombined (due to crossing-over between the two x-chromosomes
in the female producing the eggs).  Genes far apart on a chromosome
recombine more frequently than those close together.   The units of the
map were the frequency of recombination between pairs of genes.  We now
honor Morgan and designate one percent recombination on our linkage maps
as one "centiMorgan".  The principles of Sturtevant's map remain the basis
for building genetic (linkage) maps in a variety of species today.  J.B.S.
Haldane examined human pedigrees in 1937 and estimated the distance
between the genes for color blindness and hemophilia on the human
x-chromosome (the first human gene map).  Jan Mohr discovered linkage of
traits on a chromosome other than the x (autosomal linkage) in humans in
1951.  There are now many refinements for building linkage maps, the more
important being powerful statistical tools for pedigree analysis and
molecular techniques for the identification of variants in genes or DNA
sequences.  There are also many new ways to map genes other than by
linkage, such as hybridizing microscopically visable probes directly to
chromosomes.   Only in the last decade have we had human genetic maps that
permit genetic counseling for inherited diseases based on nearby markers
on the linkage map.  These maps also led us into the current era of
discovery of the actual genes responsible for the diseases.  We are also
beginning to use maps of agriculturally important plants and animals to
find markers for traits of interest and also to identify the genes
responsible for the traits.  Like most things in science, there was no
practical application of the discoveries of Sturtevant, Morgan and others
at the time their work was published.  It was just new basic knowledge
about the biology of plants and animals.  Here we are 85 years later
making practical use of these important discoveries. As to your question
of what was thought of the work at the time, I suspect it was appreciated
only by other scientists and not at all by the general public.  I hope in
your homework assignment you will find occassion to discuss the time lag
between basic scientific discovery and practical benefits to society.  I'm
afraid this fact is no more appreciated today than it was then.  Good
luck. 

Jim Womack

P.S.  I just read Andy Law's response which is a review of much more
recent history than is mine.  I believe if you piece the two together you
will have a good idea of just how many scientific advances were required
to get from the basic concept in 1913 to the various practical applications
in 1998.
From: "Mary E. Delany" <medelany_at_ucdavis.edu>
Date: Thu, 5 Mar 1998 12:16:26 -0600
To: mappers_at_iastate.edu
Subject: Re: Homework

Some points and hallmarks that might help:

Bateson coined the term "genetics" (note that later he resisted the idea of
the chromsomal basis for the units of heredity!  He also coined homozygote
and heterozygote, F1, F2).

Bateson and Punnett (1904) first reported nonrandom assortment (they didn't
know it was linkage, thought it was "replusion" of characters from opposite
parents).

It was inside Thomas Hunt Morgan's lab (ca. 1910 on at Columbia) that the
experimental evidence grew that the chromosomes were the mechanism for
inheritance. (He wrote "Theory of the Gene"). Sturtevant provided exptl
evidence for linkage in Drosophila and apparently gets credit for producing
the first genetic map (a Drosphila genetic map (1913).

W. Johannsen (studied beans) is credited for coining the terms "phenotype
and genotype" and coined the word "gene" (1909).

During the first 20-30 years of this century Poultry genetics (several land
grant institutions), drosophila genetics (Morgan's lab), maize genetics
(Cornell:  McClintock and others) associated genes/characters with
particular chromosomes and linked them (=gene mapping). (apologies if I've
missed a group).

In lieu of revisiting the original texts and research articles, King and
Stansfield's "A Dictionary of Genetics", 5th edition has a very useful
timeline, however I would say  in a strong fashion  that IT DOES NOT
CHRONICLE THE CONTRIBUTIONS OF LIVESTOCK/AGRICULTURAL RESEARCH to the fields
of genetics, cytogenetics, etc.

 --Mary Delany.
From: "andy.law" <andy.law_at_bbsrc.ac.uk>
Subject: RE: Homework
To: angenmap_at_iastate.edu
Date: Thu, 5 Mar 98 09:15:42 +0000

Dear P?

I'm sorry. Although I work on Gene Mapping Projects, I haven't got the
first clue who was the first to try it. Its a pretty old concept though -
there are some phenotypic loci (feather colour in chickens etc) that were
'mapped' in the early part of the 20th Century. The first published
chicken genetic linkage map was by one F.B.Hutt in 1936. For a review of
chicken genetic mapping, I suggest you get hold of a review published in
Trends in Genetics (1995) Volume 11, part 5 pages 190-194. For pigs, the
current key author names to search for are A.L.Archibald, L.Anderson
(spelling?) and M.F.Rothschild. If you get one of their review papers,
you should be able to work backwards through the references they provide.
If you need any help on current methodologies (and databases - thats my
involvement), then get back to me.

Later,

Andy Law
Date: Thu, 5 Mar 1998 17:50:11 +0100
To: angenmap_at_iastate.edu
From: Ingrid.Olsaker_at_veths.no (Ingrid Olsaker)
Subject: RE: Homework

I would suggest to consult a textbook in general genetics. There you will
find information about Mendel and pea-plants as well as Drosophila and
Tomas Hunt Morgan among others. (Anyone heard about cM = centiMorgan?)

Ingrid
Date: Fri, 13 Mar 1998 09:24:27 -0500
To: mappers_at_iastate.edu (AnGenMap)
From: Lyman / Margaret Crittenden <crittend_at_itis.com>
Subject: Homework

More Homework

Another source of information on genetic mapping and other approaches to
mapping such as physical mapping and sequencing is a Primer on Molecular
Genetics put for the Human Genome Project by the Department of Energy. This
can be found on the Web at:

http://www.ornl.gov/hgmis/publicat/primer/intro.html

I think you can get a print copy form The Human Genome Management
Information System, Oak Ridge National Laboratory, 1060 Commerce Park, Oak
Ridge, TN 37830 or by e-mail bkq_at_ornl.gov.


Lyman B. Crittenden 
Date: Fri, 13 Mar 1998 15:47:47 -0600
To: angenmap_at_iastate.edu
From: Zhiliang Hu <zlhu_at_iastate.edu>
Subject: Re: Homework

At 03:07 PM 3/13/98 -0600, Margaret Crittenden  wrote:

>Another source of information on genetic mapping and other approaches to
>mapping such as physical mapping and sequencing is a Primer on Molecular
>Genetics put for the Human Genome Project by the Department of Energy. This
>can be found on the Web at:
>
>http://www.ornl.gov/hgmis/publicat/primer/intro.html

 As a matter of fact, we have adopted (mirrored) the site to our U.S. PIG
 GENE MAPPING Coordination Program web site: 

    https://www.genome.iastate.edu/

 In the section: "Pig Genetics, Breeds and Production/ About Pigs: Genetics"
 we have 3 entries about "molecular biology and gene mapping":

   1. "Blue Genes": A Short Course to Genetic Inheritance
       A program designed to educate high school students
       and others on the principles of genetic inheritance.
       -- by: Laura Kingdon, Max Rothschild, and Lizhen Wang

   2. An Introduction to Genes and Gene Maps
       A description of gene mapping for pig producers, students,
       and interested persons
       -- by: Laura Kingdon, Lizhen Wang, and Max Rothschild

   3. A Primer on Molecular Genetics.
       -- by Denise Casey for the 1991-92 DOE Human Genome Program Report
             and modified for Web access by Dan Jacobson. This material
             was originally hosted at http://www.bis.med.jhmi.edu/ and 
             later adopted to this site.

 and other related materials.

 Zhiliang

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