The level of habitat availability influences genetic divergence among populations and the genetic diversity within populations. In the marine environment, near-shore species are among the most sensitive to habitat changes. Knowledge of how historical environmental change affected habitat availability and genetic variation can be applied to the development of proactive management strategies of exploited species. Here, we modeled the contemporary and historical distribution of Lutjanus jocu in Brazil. We describe patterns of genomic diversity to better understand how climatic cycles might correlate with the species demographic history and current genetic structure. We show that during the Last Glacial Maximum, there were ecological barriers that are absent today, possibly dividing the range of the species into three geographically separated areas of suitable habitat. Consistent with a historical reduction in habitat area, our analysis of demographic changes shows that L. jocu experienced a severe bottleneck followed by a population size expansion. We also found an absence of genetic structure and similar levels of genetic diversity throughout the sampled range of the species. Collectively, our results suggest that habitat availability changes have not obviously influenced contemporary levels of genetic divergence between populations. However, our demographic analyses suggest that the high sensitivity of this species to environmental change should be taken into consideration for management strategies. Furthermore, the general low levels of genetic structure and inference of high gene flow suggest that L. jocu likely constitutes a single stock in Brazilian waters and, therefore, requires coordinated legislation and management across its distribution.

To determine the role of epidermal growth factor (EGF) receptors in thyroid tumorigenesis, EGF binding was compared in membranes from malignant and from benign thyroid tumors. Surgical specimens were obtained from 28 patients with thyroid carcinomas (3 papillary, 13 follicular, 6 undifferentiated, and 6 medullary carcinomas) and from 30 patients with benign thyroid tumors (15 scintigraphically functional and 15 nonfunctional nodules). In 30 cases normal tissue adjacent to the tumor was also obtained. EGF binding was seen to be increased not only in thyroid carcinomas but also in benign thyroid tumors, particularly in functional thyroid adenomas. The highest EGF binding was found in undifferentiated carcinomas. A direct comparison of the EGF binding characteristics in tumor and adjacent normal thyroid tissue revealed that the increased binding of EGF is due mainly to an increase in the number of binding sites rather than an alteration in receptor affinities. EGF binding capacities were 18.4 +/- 16.7 fmol/mg protein in thyroid carcinomas and 10.5 +/- 5.2 fmol/mg in the corresponding normal tissue (P < 0.05, Kd 0.84 +/- 0.26 nM, n = 11). In autonomously functioning thyroid adenomas binding capacities were 14.2 +/- 8.2 fmol/mg in the nodules and 8.9 +/- 4.8 fmol/mg in normal tissue (P < 0.01, Kd 0.73 +/- 0.62 nM, n = 15). In conclusion, EGF receptor levels are increased not only in malignant thyroid tumors but also in well-differentiated benign thyroid nodules.(ABSTRACT TRUNCATED AT 250 WORDS)

A geospatial analysis of 1,906,302 records of 1938 species of Australian vertebrates has shown that the original regions proposed in the 19th century, namely the Eyrean, Torresian and Bassian still hold. The analysis has shown that the Eyrean region has an east-west divide, forming two, possibly independent arid regions (Eastern Desert and Western Desert provinces), that are shaped by topography and rainfall. A revised and interim zoogeographical area taxonomy of the Australian region is presented herein.

Temporal variation of effective population size and gene flow determine current patterns of genetic diversity within species, and hence the genetic variation upon which natural selection can act. Although such demographic processes are well understood in terrestrial organisms, they remain largely unknown in the ocean, where species diversity is still being described. Here, we present one of the first population genomic studies in a cephalopod, Octopus insularis, which is distributed in coastal and oceanic island habitats in the Atlantic Ocean, Mexican Gulf and the Caribbean Sea. Using genomic data, we identify the South Equatorial current as the main barrier to gene flow between southern and northern parts of the range, followed by discontinuities in the habitat associated with depth. We find that genetic diversity of insular populations significantly decreases after colonization from the continental shelf, also reflecting low habitat availability. Using demographic modelling, we find signatures of a stronger population expansion for coastal relative to insular populations, consistent with estimated increases in habitat availability since the Last Glacial Maximum. The direction of gene flow is coincident with unidirectional currents and bidirectional eddies between otherwise isolated populations, suggesting that dispersal through pelagic paralarvae is determinant for population connectivity. Together, our results show that oceanic currents and habitat breaks are determinant in the diversification of marine species, shaping standing genetic variability within populations. Moreover, our results show that insular populations are particularly vulnerable to current human exploitation and selective pressures, calling the revision of their protection status.