At the outset of the meiotic pairing process in man, trial and error mismatching and misalignment, both within homologous pairs and between heterologues, can be observed cytologically. Pairing starts at early zygotene principally within subtelomeric regions where the synaptonemal complex initiates. In the present paper, evidence for the primary role in synaptic initiation of a GC rich minisatel...

Reproductive cooperation confers benefits, but simultaneously creates conflicts among cooperators. Queens in multi-queen colonies of ants share a nest and its resources, but reproductive competition among queens often results in unequal reproduction. Two mutually non-exclusive factors may produce such inequality in reproduction: worker intervention or queen traits. Workers may intervene by favo...

Somerville's brief critique of ecologically unequal exchange (EUE) theory illustrates how entangled traditional labour theories value are in 19th century discourse on political economy. His incapacity to understand the point EUE reflects idealist myopia such discourse, largely oblivious material metabolism world society. For theorists genuinely committed historical materialism, should provide a...

Though the phenomenon of sister chromatid exchange (SCE) 1 has now been known for over thirty years (1-3), its biological role(s) remains poorly defined (see ref. 4). The greatest number of observations of SCE have come from cytogenetic studies using agents such as [3H]thymidine or 5-bromodeoxyuridine to label sister chromatids differentially and observe their exchange. Such studies demonstrate...

The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused...

A case of trisomy 9p syndrome is reported. The karyotype showed a tandem duplication of the short arm and of the inverted heterochromatic block of chromosome 9. Unequal sister chromatid exchange seems to be the only possible cause of this finding.