Gene identification and DNA sequence analysis in the GC-poor 20 megabase region of human chromosome 21.

ABSTRACT: In contrast to the distal half of the long arm of chromosome 21, the proximal half of approximately 20 megabases of DNA, including 21q11-21 bands, is low in GC content, CpG islands, and identified genes. Despite intensive searches, very few genes and cDNAs have been found in this region. Since the 21q11-21 region is associated with certain Down syndrome pathologies like mental retardation, the identification of relevant genes in this region is important. We used a different approach by constructing microdissection libraries specifically for this region and isolating unique sequence microclones for detailed molecular analysis. We found that this region is enriched with middle and low-copy repetitive sequences, and is also heavily methylated. By sequencing and homology analysis, we identifie

SUBMITTER: Yu J 

PROVIDER: S-EPMC21250 | biostudies-literature | 1997 Jun

REPOSITORIES: biostudies-literature