Mutation analysis of a Mauritian hereditary breast cancer family reveals the BRCA2 6503deITT mutation previously found to recur in different ethnic populations.

Mauritius, a small island some 855 km off the east coast of Madagascar, has a multiethnic population of about 1.2 million with a high population density of about 611 per km(2). The recent industrialization of the island seems to have been accompanied, in less than 10 years, by an increase of at least 30% in breast cancer incidence. We have detected the BRCA2 6503delTT mutation in two sisters of the same family of Indian origin but living in Mauritius for at least five generations. This mutation has been found to recur in geographically diverse populations and haplotype analysis has shown a common ancestry. The haplotype of the mutation found in the Mauritian family differs from that found in other populations harbouring the same mutation, suggesting that the BRCA2 6503delTT mutation most likely arose independently.

The dynamics of zooxanthellae populations: A long-term study in the field

Coral bleaching characterized by the expulsion of symbiotic algae (zooxanthellae) is an increasing problem worldwide. Global warming has been implicated as one cause, but the phenomenon cannot be fully comprehended without an understanding of the variability of zooxanthellae populations in field conditions. Results from a 6-year field study are presented, providing evidence of density regulation but also of large variability in the zooxanthellae population with regular episodes of very low densities. These bleaching events are likely to be part of a constant variability in zooxanthellae density caused by environmental fluctuations superimposed on a strong seasonal cycle in abundance.

Comparative studies of the genus echinometra from okinawa and mauritius.

Okinawan sea urchins, the genus Echinometra, are four independent species. But which species are the same species as E. mathaei and E. oblonga as described by is still open to question. To answer this question, a field survey of genus Echinometra was made in Mauritius (the type locality of E. mathaei) according to the characteristics used to classify Okinawan Echinometra: appearance, pore pairs, spicules in gonads and tubefeet, sperm shape, and distribution on a reef. The results of crossfertilization between Echinometra from Mauritius and Okinawa are also reported. Mauritian Echinometra are classified into three groups which resemble Okinawan Echinometra sp. B, D, and violet spine color Echinometra. The latter has almost the same characteristics as Okinawan Echinometra sp. B but with violet spines, a spine color not found in Okinawa. In cross-fertilization experiments, the sperm of Mauritian Echinometra sp. B-like and violet Echinometra fertilized Okinawan Echinometra sp. B with almost 100% success. However, fertilization was unsuccessful with other Okinawan Echinometra species. Therefore, it could be said that Okinawan Echinometra sp. B is the same as Mauritian Echinometra sp. B-like, and the counterparts of Okinawan Echinometra sp. A and C are not distributed in Mauritius. The descriptions of E. mathaei most match Mauritian Echinometra sp. B-like and the type locality of E. mathaei is Mauritius. Thus, it is probable that Mauritian Echinometra sp. B-like is E. mathaei. Therefore, Okinawan Echinometra sp. B, which most resembles Mauritian Echinometra sp. B-like, would be also E. mathaei. Echinometra sp. A and C would be considered to be new species. Echinometra sp. D is thought to be the same species as Mauritian black Echinometra. Whether Okinawan Echinometra sp. D is the same as E. oblonga remains as a problem for future research. Because the type locality of E. oblonga is not known and, it is suggested that the E. oblonga described in the Indo-West Pacific is a complex species.

Possible growth factors for chickens in silkworm pupae meal.

Silkworm pupae were included in the diet of growing chickens, causing little effect at 50 g/kg but a marked depression in performance at 100 g/kg. Direct comparisons of diets containing silkworm pupae of different ages indicated a growth stimulating effect correlated with ecdysteroid activity.