Analysis Of Germline Research Articles

Recombination signature of germline immunoglobulin variable genes.

In human and mouse, the germline contains a tandem array of highly homologous variable (V) gene elements which encode part of the antigen-binding region of the antibody protein. During evolution this array apparently arose by gene duplication followed by diversification of duplicated genes via point mutation and recombination. Analysis of germline V gene sequences using a novel algorithm shows that major recombination sites coincide with the borders of the leader intron and the cap site, consistent with the hypothesis that over evolutionary time cDNA derived by reverse transcription of pre-mRNA in B lymphocytes has recombined with germline DNA.

Analysis of Germline and Expressed T Cell Receptor Variable Region Genes in Crohn's Disease

A possible role of the T cell receptor genes in the pathogenesis of Crohn's disease was investigated by 1) comparison of restriction fragment length polymorphisms at the T cell receptor beta chain locus in 64 Crohn's patients and 64 normal controls; 2) semi-quantitative polymerase chain reaction analysis of T cell receptor beta and alpha chain variable region gene expression by lamina propria lymphocytes from resected segments of diseased terminal ileum. We found no association between any of the restriction fragment length polymorphisms and Crohn's disease using polymorphic markers spanning the T cell receptor beta chain locus. Analysis of T cell receptor V beta and V alpha gene expression showed that expression of T cell receptor V region families in terminal ileum lymphocytes from patients with active Crohn's disease was indistinguishable from the lymphocytes found in normal terminal ileum. These data fail to support susceptibility to Crohn's disease being associated with the T cell beta chain antigen receptor genotype. No restricted or dominant T cell receptor variable region gene expression was found in Crohn's disease tissue, compared to normal terminal ileum.

Analysis of germline and in vivo somatic mutations in the human adenine phosphoribosyltransferase gene: Mutational hot spots at the intron 4 splice donor site and at codon 87

We have characterized 18 germline and 10 in vivo somatic mutations in the human adenine phosphoribosyltransferase ( APRT) gene. Both germline and in vivo somatic mutations were clustered at the intron 4 splice donor site at codon 87. In vitro somatic mutations in human APRT do not appear to show this clustering. These findings suggest that the spectrum of germline mutations in APRT may be similar to that incurred by somatic cells in vivo, but different from that seen in cultured cells. Thus, in vivo, rather than in vitro, somatic mutations in this gene may be more representative of mutational event occurring in the germline.

Spontaneous mutation at the hypervariable mouse minisatellite locusMs6-hm: flanking DNA sequence and analysis of germline and early somatic mutation events

Hypervariability at minisatellite loci is maintained by spontaneous mutation to new-length alleles. At the most variable loci, mutation rate is directly measurable by pedigree analysis. The mouse minisatellite locus Ms6-hm has a germline mutation rate of 2.5% per gamete and is therefore one of the most unstable loci yet identified in the mouse genome. Mutation events at this locus also occur during early mouse development, resulting in mice mosaic for cells carrying a common non-parental allele in different somatic tissues and the germline. The DNA sequence flanking Ms6-hm is rich in dispersed repetitive elements; the minisatellite array has expanded from within a member of the Mouse Transcript family which is flanked by two additional Mouse Transcript elements, and a B2 element lies further 3' to the minisatellite. To define the characteristics of mutation events at Ms6-hm we have analysed 19 germline and 13 somatic length-change events. Germline mutation events at Ms6-hm are not accompanied by the exchange of flanking markers in three informative mutant alleles analysed.

ANALYSIS OF THE DIPLOID GERMLINE OF PLANTS BY MUTATIONAL TECHNIQUES

Methods and pitfalls of analysis of the diploid germline are outlined. Attention is called to the fact that mutation recovery after seed-treatment is most effective when the maximal number of M1families are screened in minimal size M2.