Increases in Genetic Diversity of Weedy Rice Associated with Ambient Temperatures and Limited Gene Flow.

Hypotheses regarding the association of increased species or genetic diversity with gradually warmer regions as a global pattern have been proposed, but no direct and solid experimental data are available to approve the association between plant genetic diversity and ambient temperatures. To test the diversity-temperature hypothesis, we studied genetic diversity and genetic differentiation of weedy rice (Oryza sativa f. spontanea) populations occurring naturally in early- and late-season rice fields that share nearly the same ecological conditions but with slightly different temperatures. Data collected from 10-year historical climatic records indicated a ~2 ℃ higher average air temperature in the late rice-cultivation seasons than in the early seasons. Results based on molecular fingerprints of 27 SSR (simple sequence repeat) loci showed a higher level of genetic diversity in the late-season weedy rice populations than in the early-season populations. In addition, a positive correlation was detected between the increased proportion of genetic diversity (ΔHe ) and genetic differentiation among the weedy rice populations, suggesting limited gene flow. Therefore, we conclude from this study that increased genetic diversity in the late-season weedy rice populations is probably caused by the higher ambient temperatures. This finding provides evidence for the possible association between genetic diversity and ambient temperatures.

[Comparation on Haversian system between human and animal bones by imaging analysis].

OBJECTIVE: To explore the differences in Haversian system between human and animal bones through imaging analysis and morphology description. METHODS: Thirty-five slices grinding from human being as well as dog, pig, cow and sheep bones were observed to compare their structure, then were analysed with the researchful microscope. RESULTS: Plexiform bone or oeston band was not found in human bones; There were significant differences in the shape, size, location, density of Haversian system, between human and animal bones. The amount of Haversian lamella and diameter of central canal in human were the biggest; Significant differences in the central canal diameter and total area percentage between human and animal bones were shown by imaging analysis. CONCLUSION: (1) Plexiform bone and osteon band could be the exclusive index in human bone; (2) There were significant differences in the structure of Haversian system between human and animal bones; (3) The percentage of central canals total area was valuable in species identification through imaging analysis.

[New improved approaches for DYS385 detection].

OBJECTIVE: To establish more sensitive methods for detection of DYS385 in routine forensic casework. METHODS: The primers recommended by Genome Database (GDB) and Schneider were used to amplify DYS385 respectively. Then, a semi-nested PCR of DYS385 was designed by using the two different primers as outer and inner primer. A series of experiments were carried out to achieve good result by adjusting the ratio of outer/inner primer and optimizing the PCR condition. RESULTS: It showed that an overall 112 bp shorter DYS385 fragments and better electrophoretic separation were obtained by using primer2B. By using the semi-nested PCR approach, the shorter specific DYS385 fragments could be amplified and detectable DNA amounted to 50 pg. CONCLUSION: This method is 20 fold more sensitive than the ordinary method.