Four cytological races of Scilla aututn.na/is, Liliaceae, were found in a study of 31 populations from Spain and Portugal. Two are diploids with 2n 14, designated AA and B7B7, which differ by 70 per cent in DNA content, one is an allotetraploid AAB7B7 and one an autotetraploid of the B7 genome. Races AA and AAB7B7 are Iberian endemics, B7B' is widespread throughout the Mediterranean, while the autotetraploid is the common European race. In Iberia, the races are parapatric and distribution is not related to climatic conditions. The populations are chromosomally heterogeneous. Polymorphisms include B-chromosomes (five types) and supernumerary segments. Large euchromatic segments occur on the homoeologues Al and Bi in both diploids and the allotetraploid, converting these acrocentrics to metacentrics. A wide spectrum of non-polymorphic numerical and structural variants was also found. The chromosomal structure of this species complex is discussed.polyploid complex, population structure, super-

The genus Khoratpithecus, a hominoid thought to be related to the orangutan lineage, is represented by two known fossil species K. chiangmuanensis and K. piriyai. Both were discovered in Southeast Asia (Thailand) and are dated to the Middle and Late Miocene, respectively. In this study, dental topographic and microwear texture analyses were used to examine molars from both of these species, with the goal of understanding their dietary preferences. Although sample sizes are small for Khoratpithecus, available data are compared to that collected for extant apes. Environmental evidence, such as botanical remains and sedimentological data, is also considered for comparisons with dietary reconstruction. Results from dental topographic analysis suggest that the two fossil species were better adapted to a diet of fruits than to one of leaves, much like the living orangutan or chimpanzee. Results from microwear texture analysis further support this, suggesting that Khoratpithecus preferred soft fruits to hard fruits or seeds. And finally, the botanical and sedimentological evidence point to environments for Khoratpithecus that would have been compatible with a fruit-eating species. Given the small sample sizes available for analysis, however, definitive judgments are not yet possible at this time.

Scilla autumnalis, a bulbaceous perennial member of the Liliaceae, is widespread throughout much of Europe and North Africa. So far it has been classified as a single species, primarily on morphological grounds. This paper reports 10 cytologically distinct races of the plant present over the range of distribution, and hypothesizes the existence, at least at some stage of the evolution of the complex, of two additional races. At least five distinct genornes are described, involving chromosomal rearrangements, changes in DNA amount and three levels of ploidy. A picture of the evolutionary relationships of the cytotypes is suggested.

Jackson DC, Taylor SE, Asare VS, Villarnovo D, Gall JM, Reese SA. Comparative shell buffering properties correlate with anoxia tolerance in freshwater turtles.

Patterns of diversity in pathogen genomes provide a window into the spatiotemporal spread of disease. In this study, we tested the hypothesis that Schistosoma mansoni parasites form genetic clusters that coincide with the communities of their human hosts. We also looked for genetic clustering of parasites at the sub-community level. Our data consists of 14 microsatellite DNA markers, typed from pooled DNA samples from $$N=254$$ N = 254 infected individuals living in three Brazilian communities. We found a one-to-one correspondence between genetic clusters found by K-means cluster analysis and communities when $$K = 3$$ K = 3 . These clusters are also easily identified in a neighbor-joining tree and principal coordinates plots. K-means analysis with $$K > 3$$ K > 3 also reveals genetic clusters of parasites at the sub-community level. These sub-clusters also appear on the neighbor-joining tree and principal coordinates plots. A surprising finding is a genetic relationship between subgroups in widely separated human communities. This connection suggests the existence of common transmission sites that have wide influence. In summary, the genetic structure of S. mansoni in Brazil juxtaposes local isolation that is occasionally broken by long-range migration. Permanent eradication of schistosomes will require both local efforts and the identification of regional infection reservoirs.