Genetic mapping: Chromosomes 2?5

Abstract

Genetic maps of chromosomes 2 and 4 constructed from pair-wise lod score data from family studies and regional assignments for markers are presented. Two loci are mapped on chromosome 2 and multiple crossing-over is suggested as an explanation for the poor fit to the data in females. The best map of chromosome 4 gives the genetic locations of five markers with the Stoltzfus (SF) blood group distal to MNS on the long arm and GC close to the centromere on the short arm. This position for GC is outside its provisional regional assignment and possible reasons for this discrepancy are discussed. The GM-PI linkage group has a score of less than -1.0 with chromosome 4 suggesting that it may be excluded from that chromosome. The regional assignment for markers on chromosome 2-5 are also shown.

Analysis of the monomeric alphoid sequences in the pericentromeric region of human chromosome 7

“…Therefore, D7S1480 and D7S494 are the polymorphic markers nearest the chromosome 7 centromere on the short and long arms, respectively, and can be used as anchor markers for the centromere. The recombination rate between D7S1480 and D7S494 was zero, corroborating that meiotic recombination is significantly reduced across the centromere (Keats, 1982;NIH/CEPH Collaborative Mapping Group, 1992). Completion of the physical map across the centromere of human chromosome 7 will permit the exact definition of the relationship between the physical and genetic distances across the centromere and in its flanking regions.…”

C3 Polymorphism in Beta-Thalassemia

“…After our study this hypothesis remains open to research. The explanation of these results on a genetic basis is difficult but, as C3 has been only provisionally assigned to chromosome 19 [12], a new possibility for the situation of its locus near those controlling the production of hemoglobin chains is emerging. Family studies which ought to be carried out may offer confirm atory data to this hypothesis.…”

Evolutionary implications of pericentromeric gene expression in humans

“…These regions have long been known to be both recombination deficient (Keats, 1982;Jackson et al, 1996;Puechberty et al, 1999) and rich in satellite sequences (reviewed in Lee et al, 1997). Both directed analyses of specific pericentromeric regions (Guy et al, 2000(Guy et al, , 2003Brun et al, 2003) and global analysis of draft sequence data ) have established that a high proportion of pericentromeric sequences have been subject to recent duplication events, with the most proximal 2 Mb on all chromosome arms being enriched 4.5-fold for interchromosomal duplications and 3.1-fold for intrachromosomal duplications .…”