Back to Mammalian Molecular Genetics Group Projects
J main objective of the Human Genome Project is to make a series of genetic linkage, physical and transcription maps of all human chromosomes at increasingly finer resolution and to assemble overlapping sets of clones spanning the entire chromosome in order to facilitate gene isolation, particularly in cases where the respective mRNA or polypeptide is unidentifiable. The ultimate goal of the project is to determine the sequence of all human genes and develop tools for using this information in human biology and medicine.
Human chromosome 10 is a medium size sub-metacentric chromosome representing 4.6% of the total length of the autosomes. More than a hundred genes (i.e. about 2.5% of the totally expected number) and about 20 genetic diseases, e.g., multiple endocrine neoplasia type 2A and 2B (MEN2A, 2B), familial medulary thyroid carcinoma (FMTC), DiGeorge syndrome (10p13), Hirschsprung disease, etc., have been documented as being associated with gene loci mapped to chromosome 10. Interestingly, it has been recently suggested that the gene(s) associated with early stages of the development of certain types of cancer, including prostate cancer, glioblastoma multiforme and melanocytic neoplasia, are possibly located at the distal region of 10q.
2.1. Bridging the Genetic with the Physical Map
Positional cloning of disease genes, such as those mentioned above, will be extremely facilitated by the construction of high resolution genetic linkage and physical maps. We have recently constructed a well-supported map of chromosome 10 containing 57 highly polymorphic markers (mean genetic distance 4.8 cM) ordered with odds >1000:1. Most of the genotypic data was obtained by screening the entire set of the 40 CEPH families with genetic markers, mostly of the microsatellite type. Some of the markers, initially identified in our lab, were also mapped on chromosome 10 by means of fluorescence in situ hybridization (FISH). Our current work for the improvement of the genetic map of chromosome 10 and its correlation with the physical and the cytogenetic map includes further screening of the CEPH families with novel microsatellite markers, either identified locally after systematic screening of chromosome 10-specific genomic libraries or provided through the EUROGEM network. Our aim is to construct a comprehensive and high resolution well-supported genetic linkage map with a mean genetic distance of 1-2 cM and to propose the respective meiotic breakpoint map. Moreover, in order to correlate genotypic data with the physical map, we are in the process of the identification of ICI YAC clones corresponding to novel microsatellite markers and the determination of their cytogenetic location using FISH. In addition, high resolution YAC and cosmid contigs will be prepared for the 10q24-26 region where tumor suppression gene(s) are possibly located.
2.2. The Transcription Map of 10q24 Region
Deletions of 10q24 have been observed in various tumor types. Physical mapping in various laboratories, including ours, has led to the identification of a number of YACs mapped to this area. Tumors from patients with prostate cancer have been analyzed and two highly specific regions of deletions have been identified in 10q24 (N. Spurr, personal communication). The aim of this collaborative project (NKM, N. Spurr and C. Nobile) is to identify as many of the genes in this region as possible using a number of different selection techniques (e.g., hybridization selection, exon trapping, etc.) to position these genes on the YAC contig and to isolate and sequence a full-length cDNA clone for each one. These cDNAs will be used to study the pattern of RNA expression in human adult, fetal and tumor tissues. This will allow us to construct both a detailed transcription map of the region and to build a picture of the pattern of gene expression, leading to a greater understanding of the regulation of genes in this region. In addition, we plan to convert selected map areas into tiling paths of smaller P1 or cosmid clones in a sequence-ready format.
Back to Mammalian Molecular Genetics Group Projects
Back to the Mammalian Molecular Genetics Group Home Page
IMBB's
Home Page[ Groups & Activities / Greek National Embnet node / Facilities / Interesting Sites / Other Personnel / IMBB Contacts ]