Integrated transcription and physical map from the region of chromosome 21 around locus D21S55
- Harvard Medical School, Boston, MA (United States); and others
Expressed sequences from an {approximately}3 Mb region of chromosome 21 around locus D21S55 that is believed to be important in contributing to some features of Down syndrome have been isolated by exon amplification from pools of chromosome 21 cosmid DNA. A minimum set of YAC clones covering the majority of this region was used to identify 394 corresponding cosmids from a chromosome 21-specific library generated by Lawrence Livermore National Laboratory. DNA from pools of these cosmids was used to isolate gene fragments. To date, 74 unique exons have been isolated and sequenced and over 200 additional exons are expected from the remaining cosmid pools. These gene fragments are being correlated with the YAC physical map of chromosome 21 by hybridization to YAC colony grids. They are also being utilized to increase the resolution of the physical map by relating the cosmids from which they were isolated to each other as well as the YACs. The result of assessing the presence of the exons and STS in the cosmids and YACs is the emergence of a gene map where the location of gene fragments and their physical distance from genetic makers is known. Currently, 44 exons have been localized on the YAC and cosmid physical map of chromosome 21. Of 12 exons hybridized to Southern blots of genomic DNA from human, mouse, hamster and somatic cell hybrids, all 12 localized to chromosome 21. Five of these exons were conserved in rodent DNA and 2 hybridized to one or more additional human bands, suggesting 2 different gene families with a member on chromosome 21. Five exons from the ERG gene localized in this region were isolated. The remaining exons have no significant similarity with reported sequences. Isolation of cDNA clones is accomplished by PCR- and hybridization-based methods. Continued characterization of these exons will aid in the isolation of genes from regions of interest on chromosome 21 as well as contribute to the construction of a gene map for this chromosome.
- OSTI ID:
- 134440
- Report Number(s):
- CONF-941009--
- Journal Information:
- American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
- Country of Publication:
- United States
- Language:
- English
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