Repeated polyploidization of Gossypium genomes and the evolution of spinnable cotton fibres.

Polyploidy often confers emergent properties, such as the higher fibre productivity and quality of tetraploid cottons than diploid cottons bred for the same environments. Here we show that an abrupt five- to sixfold ploidy increase approximately 60 million years (Myr) ago, and allopolyploidy reuniting divergent Gossypium genomes approximately 1-2 Myr ago, conferred about 30-36-fold duplication of ancestral angiosperm (flowering plant) genes in elite cottons (Gossypium hirsutum and Gossypium barbadense), genetic complexity equalled only by Brassica among sequenced angiosperms. Nascent fibre evolution, before allopolyploidy, is elucidated by comparison of spinnable-fibred Gossypium herbaceum A and non-spinnable Gossypium longicalyx F genomes to one another and the outgroup D genome of non-spinnable Gossypium raimondii. The sequence of a G. hirsutum A(t)D(t) (in which 't' indicates tetraploid) cultivar reveals many non-reciprocal DNA exchanges between subgenomes that may have contributed to phenotypic innovation and/or other emergent properties such as ecological adaptation by polyploids. Most DNA-level novelty in G. hirsutum recombines alleles from the D-genome progenitor native to its New World habitat and the Old World A-genome progenitor in which spinnable fibre evolved. Coordinated expression changes in proximal groups of functionally distinct genes, including a nuclear mitochondrial DNA block, may account for clusters of cotton-fibre quantitative trait loci affecting diverse traits. Opportunities abound for dissecting emergent properties of other polyploids, particularly angiosperms, by comparison to diploid progenitors and outgroups.

Clinical testing for tears of the glenoid labrum.

PURPOSE: With the increasing use of shoulder arthroscopy, diagnosis of glenoid labral lesions has become increasingly common. However, a physical examination maneuver that would allow a definitive clinical diagnosis of a glenoid labral tear, and more specifically a SLAP lesion, has been elusive. This study correlated the results of commonly used examination maneuvers with findings at shoulder arthroscopy. The working hypothesis was that 7 commonly used clinical tests, alone or in logical combinations, would provide diagnoses with reliability greater than the accepted standards for magnetic resonance imaging arthrography; i.e., greater than 95% sensitivity and specificity. TYPE OF STUDY: Consecutive sample, sensitivity-specificity study. METHODS: Sixty shoulders undergoing arthroscopy for a variety of pathologies were examined before surgery. All subjects submitted to the Speed test, an anterior apprehension maneuver, Yergason test, O'Brien test, Jobe relocation test, the crank test, and a test for tenderness of the bicipital groove. The examination results were compared with surgical findings and analyzed for sensitivity and specificity in the diagnosis of SLAP lesions and other glenoid labral tears. RESULTS: The results of the O'Brien test (63% sensitive, 73% specific) and Jobe relocation test (44% sensitive, 87% specific) were statistically correlated with presence of a tear in the labrum and the apprehension test approached statistical significance. Performing all 3 tests and accepting a positive result for any of them increased the statistical value, although the sensitivity and specificity were still disappointingly low (72% and 73%, respectively). The other 4 tests were not found to be useful for labral tears, and none of the tests or combinations were statistically valid for specific detection of a SLAP lesion. CONCLUSIONS: Clinical testing is useful in strengthening a diagnosis of a glenoid labral lesion, but the sensitivity and specificity are relatively low. Thus a decision to proceed with surgery should not be based on clinical examination alone.

Arthroscopic treatment of a symptomatic hip plica.

Synovial plicae are detected most readily by diagnostic arthroscopy. As arthroscopic techniques are applied more frequently to various joints, it should be expected that the diagnosis of plica syndrome will become more common. The authors present a case of symptomatic plica in the hip of a competitive runner, who was treated with arthroscopic resection.