Report of the Committee on Human Gene Mapping by Recombinant DNA techniques (Part 1 of 9)

Critical role of the D21S55 region on chromosome 21 in the pathogenesis of Down syndrome.

“…Only IG was informative and the equal intensities of the two bands, as observed in heterozygote control subjects, confirmed that D21SJ7 was not duplicated. In the absence of DNA from FG and IG's parents, multiallelic and more complex Xba I/D21S55 (34) and Msp I/ETS2 (35) RFLPs could not be informative.…”

Structure of Human Chromosome 21—For an Understanding of Genetic Diseases Including Down’s Syndrome—

“…However, its nonrandom nature suggests that it reflects some aspect of genome organization of chromosome 21. lt has become increasingly clear that genes are neither randomly nor uniformly distributed throughout the genome, which suggests that two-thirds to three-quarters of genes are located in Giemsa light bands.~·0. [47][48][49][50] Consider the four physical linkage groups within 21q22.3. Together they involve a total of 14 unique sequences, of which seven are cDNAs of identified products (ETS2, MXl, MX2, CBS, COL6Al, COL6A2, and BCEl).…”

The Application Of Recombinant DNA Technology For Genetic Probing In Epidemiology

“…Initially most DNA cloning was directed toward specific genes, particularly disease-related loci, but the concept of a human genetic linkage map based on polymorphic DNA markers distributed throughout the genome has prompted the characterization of "anonymous" DNA probes by their relative map positions (8, 60, 107). More than 2800 DNA clones have been assigned to individual chromosomes, and about 1000 have identified DNA sequence polymorphisms (79,105). Theoretically only about 300 such DNA probes should be required to "sat urate" the human genome so that all markers can be linked, but this assumes that all are equally spaced and identify informative DNA polymorphisms (1).…”

“…Theoretically only about 300 such DNA probes should be required to "sat urate" the human genome so that all markers can be linked, but this assumes that all are equally spaced and identify informative DNA polymorphisms (1). Unfortunately, as many probes are clustered in relatively small regions, several segments of the human chromosomes are not well represented (23,79).…”