A hypervariable region at the D19S11 locus

Summary The polymorphic locus D19S11 consists of four closely linked RFLPs: , , and on chromosome 19p13.219cen, revealed by subclones p13-1-82 and p13-2-21 from cosmid 1–13. Here, we report that p13-1-25, an additional subclone of c1-13, reveals three insertion/deletion RFLPs, , , and , at the D19S11 locus. In situ hybridization of p13-1-25 to metaphase chromosomes from a carrier of a 19/X translocation with a breakpoint near the centromere confirms localization of D19S11 to 19p. Studies with hydatidiform moles have generated assignments of specific restriction fragments to these three loci, and genotypic studies in three-generation families have indicated that they are closely linked. Loci (also detected by p13-1-82) and each have but two common alleles, whereas has at least 33 alleles, including a null allele. Fifty unrelated individuals tested displayed unique fragment patterns on Taq I blots probed with p13-1-25. Applications of this probe include monitoring loss of chromosome 19 during tumorigenesis, monitoring engraftment of donor bone marrow after transplantation, testing for paternity, and mapping disease genes on chromosome 19.     

The human histone gene cluster at the D6S105 locus

The sequences and organization of the histone genes in the histone gene cluster at the chromosomal marker D6S105 have been determined by analyzing the Centre d’étude du Polymorphisme Humain yeast artificial chromosome (YAC) 964f1. The insert of the YAC was subcloned in cosmids. In the established contig of the histone-gene-containing cosmids, 16 histone genes and 2 pseudogenes were identified: one H1 gene (H1.5), five H2A genes, four H2B genes and one pseudogene of H2B, three H3 genes, and three H4 genes plus one H4 pseudogene. The cluster extends about 80 kb with a nonordered arrangement of the histone genes. The dinucleotide repeat polymorphic marker D6S105 was localized at the telomeric end of this histone gene cluster. Almost all human histone genes isolated until now have been localized within this histone gene cluster and within the previously described region of histone genes, about 2 Mb telomeric of the newly described cluster or in a small group of histone genes on chromosome 1. We therefore conclude that the data presented here complete the set of human histone genes. This now allows the general organization of the human histone gene complement to be outlined on the basis of a compilation of all known histone gene clusters and solitary histone genes. Received: 30 June 1997 / Accepted: 3 September 1997     

A new EcoRI polymorphism at the D21S13 locus

Summary The D21S13 locus has shown linkage to a gene for familial Alzheimer disease (FAD) on chromosome 21 (St. George-Hyslop et al. 1987). The limited informativeness of probes for this locus have hindered precise mapping of the FAD locus and analysis of nonallelic heterogeneity in FAD (Schellenberg et al. 1988; St. George-Hyslop et al. 1987). We describe a new EcoRI polymorphism at the D21S13 locus that may be useful for the further study of FAD families.     

A new HaeIII polymorphism at the D21S13 locus

Summary DNA markers in the pericentromeric region of human chromosome 21 have shown linkage to a gene for Familial Alzheimer disease (FAD; St. George Hyslop et al. 1987). The limited informativeness of probes for the loci D21S13 and D21S16 have hindered precise mapping of the FAD locus and analysis of non-allelic heterogeneity in FAD (Schellenberg et al. 1988; St. George-Hyslop et al. 1987). We recently described a new EcoRII polymorphism at the D21S13 locus that was very informative in a large FAD pedigree (Pulst et al. 1990a, b). We now report another polymorphism for the D21S13 locus that further increases the informativeness of this locus.