REVIOUS work has shown that populations of Drosophila pseudoobscura which inhabit localities only a few miles apart may differ in the incidence of certain genetic variants. Furthermore, the composition of a population may change with time; the changes are either cyclic, paralleling the annual succession of seasons, or exhibit more sustained trends which may last for several years. Thus, the pop...

Haemophilus influenzae is a ubiquitous colonizer of the human respiratory tract and causes diseases ranging from otitis media to meningitis. Many H. influenzae isolates express pili (fimbriae), which mediate adherence to epithelial cells and facilitate colonization. The pilus gene (hif) cluster of H. influenzae type b maps between purE and pepN and resembles a pathogenicity island: it is presen...

Chromosomal inversions allow genetic divergence of locally adapted populations by reducing recombination between chromosomes with different arrangements. Divergence between populations (or hybridization between species) is expected to leave signatures in the neutral genetic diversity of the inverted region. Quantitative expectations for these patterns, however, have not been obtained. Here, we ...

In a natural population of Drosophila persimilis (McDonald Ranch, Napa Valley, California), KL and MD chromosomal arrangement frequencies undergo a seasonal cycle, with MD common in spring and KL common in summer. Samples collected from spring and summer provided isofemale strains established as homozygous KL and MD pairs (kinlines) with each pair derived from a single heterokaryotype wild prog...

spontaneous abortion (sab) is the most common complication of early pregnancy. numerous risk factors are associated with an increased risk of pregnancy loss such as: blighted ovum. the aim of this study was to determine the frequency of balanced chromosomal translocations in couples with a history of recurrent spontaneous abortions and ultrasound diagnosed blighted ovum. sixty eight couples wit...

ALK (anaplastic lymphoma kinase) is oncogenic in several tumours and has recently been identified as a predisposition gene for familial NB (neuroblastoma) harbouring mutations in the TKD (tyrosine kinase domain). We have analysed a large set of sporadic human NB primary tumours of all clinical stages for chromosomal re-arrangements using a CGH (comparative genomic hybridization) array (n=108) a...

Data are presented concerning the gene arrangements in both arms of the X-chromosome of Drosophila robusta in eight altitudinal transects. The major change appears to be the increase of gene arrangement XL-1 (and decrease in XL, sometimes also XL-2) with increasing altitude. In each transect only one combination of XL-1 with a right arm arrangement seems primarily responsible for the increases ...

Seasonal changes in gene arrangement and allozyme frequencies have been investigated in Drosophila subobscura for several years. Some arrangements (O(st) and O(3+4+7)) show seasonal variation, which suggests that chromosomal polymorphism is flexible in this species. Seasonal changes in allozyme frequencies for Lap and Pept-1 loci, both located within the same inversions of chromosome O, are sig...

Paracentric inversions in populations can have a profound effect on the pattern and organization of nucleotide variability along a chromosome. Regions near inversion breakpoints are expected to have greater levels of differentiation because of reduced genetic exchange between different gene arrangements whereas central regions in the inverted segments are predicted to have lower levels of nucle...

The cactophilic Drosophila buzzatii (buzzatii complex ± repleta group, Ruiz & Wasserman, 1993) is native to South America and has attained a subcosmopolitan distribution by following passively its native host plants of the genus Opuntia. Studies in natural populations have shown that second chromosome polymorphic arrangements affect life history traits and morphometric traits associated with ®t...