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Center Web site for chromosome studies
With AIDS and Ebola viruses spreading from monkeys to humans and researchers contemplating marrow transplants using baboon donors for human patients, it is easy to see that human medical research is intertwined with primate research.
The Center has no monkeys, but it has perhaps one of the most comprehensive primate cytogenetics databases in the world thanks to Tim Knight of Image Analysis.
During the day, Knight is an image analysis
specialist but at night he is a primatologist. He often works into the
wee hours, designing and adding information to his Primate Cytogenetics
Network and a complementary Primate Gallery on the World Wide Web.
He began his primate research 12 years ago as a volunteer at the Woodland Park Zoo. He was studying zoology at the University of Washington and was interested in a species of African primate commonly called de Brazza monkeys. Knight initiated research on the behavior, vocalizations and color development of these unique primates.
At the time, the zoo had acquired a new juvenile de Brazza monkey from another zoo to serve as the future breeding male. Zoo staff contacted Knight to verify the identification of this animal because the juvenile had an unusual coat pattern and coloration that staff had not previously observed. Knight thought the individual was probably a color variant of de Brazza monkey, but there was the possibility that the animal was a hybrid or subspecies.
De Brazza monkeys have a variable coloration
pattern through different stages of development. "Variability in coat
coloration led to de Brazza monkeys being classified as at least four distinct
species by early taxonomists" Knight says.
He was working in a cytogenetics laboratory, so he obtained some tissue samples of the juvenile, applied comparative cytogenetics techniques, and karyotyped (analyzed and characterized the chromosomes) all the de Brazza monkeys at the zoo.
In the process he searched the literature and found that primatologists had listed de Brazza monkeys with three different diploid numbers, or total number of chromosomes, 58, 60 and 62.
"A given species has a specific number of chromosomes in normal animals. Humans for example have 46. When different numbers of chromosomes are shown for two similar animals, one is considered a subspecies or distinct species," Knight explains.
His discovery of color variation in de Brazza monkeys was verified while visiting over fifty zoos all over Europe and North America. At the same time he photographed hundreds of the monkeys and conducted an extensive literature search.
He concluded
from his cytogenetic research that de Brazza monkeys have 62 chromosomes
and the juvenile male at the zoo was just a color variant. He was unable
to determine, however, whether the two reports of 58 and 60 chromosomes
were mistakes or subspecies. Knight says that those reports were done before
modern cytogenetics techniques and errors were common (up until 1956 humans
were listed as having between 37 and 48 chromosomes).
In the process, he accumulated a substantial database of over 700 journal articles ranging from 1922 to the present and developed a library of photographs.
He also developed a successful method for ensuring that tissue samples of primates collected during regular medical exams are not contaminated, which is essential for producing reliable karyotype results.
Thus far he has fully characterized the chromosomes of four of the 233 species of primates.
In November 1994 he began developing a World Wide Web site for the Image Analysis Laboratory. As he learned how to produce the hypertext pages, he realized that his cytogenetics database is particularly well suited to being organized as a web site.
One major reason is that pictures of chromosomes can be stored on computers at a resolution that allows scientists to actually do comparative studies.
This is very difficult to do via journal articles, because many articles on primate cytogenetics do not include photos and those that do are hard to come by. Most of the time, the only way to get a particular article is through inter-library loan and then what is sent is a photocopy, which eliminates any ability to conduct a comparative study.
He is also developing an extensive library of ideograms (drawings of chromosomes). Researchers can turn to his web site and download a copy of the particular ideogram they need rather than draw it themselves from scratch.
Knight designed the Primate Cytogenetics Network to be a cooperative resource that he hopes others will contribute to. He has also linked his page to the Primate Info Net, Net Vet- Electronic Zoo and other primate web sites. The Global Network Navigator, better known as the home of the Online Whole Internet Catalog, in August, featured Knight's Primate Gallery - a digital image archive of monkeys and apes. GNN is a popular Internet directory containing links to over 1,000 of the best resources on the Internet.
Knight sees the primary use of the cytogenetics network as a resource for researchers doing comparative cytogenetics studies. A secondary use will be a repository of the latest methods for harvesting tissues for karyotyping and an image bank that scientists can use to download ideograms for research papers.
Knight is also assisting Dr. Karen Dyer with graphics for a chapter on molecular cytogenetics for the ACT Cytogenetics Manual and he is presenting a paper on his network at the National Conference of the American Zoological and Aquarium Association in September.
To reach Knight's web site:
For more questions or more information, contact Knight at Ext. 4030 or by e-mail.
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