Our goal, working with many other scientists against cancer, is to understand normal cell processes that go wrong in tumors. Our group uses model systems in which these processes can be more easily studied than in tumors. One of these models has been, for many years, cell differentiation during spermatogenesis. We have characterized changes in chromatin composition and structure and changes in gene expression during the differentiation of the male gamete. We are now mainly interested in the study of the processes of cell death and survival during testicular development and regression. Formation of new vessels, angiogenesis, and vascular regression are crucial for these phenomena and could help us to understand key mechanisms involved in tumor development and metastasis.  

As an initial approach to the study of gene expression in human tumors we use simplified avian models. Why? The journal Science commented the value of an old favorite, the chicken, as a shortcut to finding human gene functions. The chicken genome has the same repertoire of genes as do mice and people, but packs them into a much smaller amount of DNA, with much less "junk" in between. You can expect to find several of the animal's genes along a length of DNA that in humans would yield only one. "You get more genes for your money" says geneticist Ben F. Koop, at the CEH (University of Victoria).  Peter Parham (Stanford University) refers that in the 300 millions years since chickens and humans shared common ancestors, their genes have evolved along wildly different trajectories: the former emphasizing economy, efficiency and teamwork; the latter going for expansion, extravagance and individualism. Birds are renowned for their frugality with DNA (Hughes & Hughes, Nature 377, 391) and in this the major histocompatibility complex (MHC) is no exception. While the human complex comprises 3,600 kilobases embracing 128 functional genes and 96 pseudogenes, the chicken has only 19 genes in 92 kilobases. Everything to do with the chicken MHC bespeaks of getting the biggest bang for the cluck: introns  and intergenic regions are short, pseudogenes absent and repetitive elements few (Nature, 401, 870). The study of the chicken genome is an excellent approach to the human genome because the organization of the human genome is closer to that of the chicken than the mouse (Burt et al. 1999, Nature 402, 411-413). 

Homepage | Email us | Comments | Search | Site Map ]

Send mail concerning this page to: webmaster@physiolgenet.com