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171.
PCR-based assays of mendelian polymorphisms from anonymous single-copy nuclear DNA: techniques and applications for population genetics 总被引:5,自引:0,他引:5
This paper outlines a PCR-based approach for population genetics that
offers several advantages over conventional Southern blotting methods for
revealing restriction-fragment-length polymorphisms (RFLPs) in nuclear DNA.
Primers are constructed from clones isolated from a nuclear DNA library,
and these primers subsequently are employed in in vitro syntheses of
homologous regions. Amplified products are then screened directly for RFLPs
by using gel-staining procedures. Population applications for this
PCR-based approach, including potential strengths and weaknesses, are
exemplified by two RFLP data sets generated to estimate (a) male-mediated
gene flow in the green turtle (Chelonia mydas) and (b) geographic
population genetic structure in the American oyster (Crassostrea
virginica). Restriction assays of amplified products from 14 or 15
independent primer pairs in each species revealed polymorphisms at several
loci that proved highly informative in the population genetic analyses. In
general, the Mendelian polymorphisms produced by this PCR-based approach
will provide useful genetic markers for population studies, particularly in
situations where simpler and less expensive allozyme methods have failed,
for whatever reason, to provide adequate information.
相似文献
172.
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174.
Effects of intrinsic and extrinsic factors on the diet of Bathyraja macloviana,a benthophagous skate
S. A. Barbini L. B. Scenna D. E. Figueroa J. M. Díaz de Astarloa 《Journal of fish biology》2013,83(1):156-169
The effects of intrinsic (sex, maturity stage and body size) and extrinsic (depth and region) factors on the diet of Bathyraja macloviana, in the south‐west Atlantic Ocean, were evaluated using a multiple‐hypothesis modelling approach. Bathyraja macloviana fed mainly on polychaetes followed by amphipods, isopods and decapods. Effects of intrinsic and extrinsic factors on diet composition of this species were found. The consumption of polychaetes had a humped relationship with total length (LT), and isopods and decapods increased with increasing LT. Immature individuals preyed on amphipods more heavily than mature individuals. Furthermore, region and depth had an important effect on the consumption of isopods, decapods and amphipods. Such ontogenetic changes and spatial patterns may provide insights into understanding the regulatory mechanisms of marine communities. 相似文献
175.
176.
177.
A distinctive feature of prokaryotic Na+-channels is the presence of four glutamate residues in their selectivity filter. In this study, how the structure of the selectivity filter, and the free-energy profile of permeating Na+ ions are altered by the protonation state of Glu177 are analyzed. It was found that protonation of a single glutamate residue was enough to modify the conformation of the selectivity filter and its conduction properties. Molecular dynamics simulations revealed that Glu177 residues may adopt two conformations, with the side chain directed toward the extracellular entrance of the channel or the intracellular cavity. The likelihood of the inwardly directed arrangement increases when Glu177 residues are protonated. The presence of one glutamate residue with its chain directed toward the intracellular cavity increases the energy barrier for translocation of Na+ ions. These higher-energy barriers preclude Na+ ions to permeate the selectivity filter of prokaryotic Na+-channels when one or more Glu177 residues are protonated. 相似文献
178.
Donald SA McLeod 《The Clinical biochemist. Reviews / Australian Association of Clinical Biochemists》2010,31(1):9-19
This paper provides an overview on the biology, monitoring and management of differentiated thyroid cancer (DTC), with particular attention to issues of relevance to clinical chemistry. The incidence of DTC appears to be increasing and management strategies are evolving as we learn more about its natural history and response to therapy. Clinical chemistry techniques play a central role in these protocols. Technical limitations inherent in current monitoring tools can hamper follow-up, although progress is being made. The molecular basis of DTC is being delineated with the potential to develop new strategies for diagnosis, monitoring and management of this condition. 相似文献
179.
Several fundamental questions remain enigmatic concerning human olfactory
sensitivity, including (i) whether detection threshold differences exist
between the two sides of the nose (and, if so, whether such differences are
influenced by handedness) and (ii) whether bilateral (i.e. binasal)
stimulation leads to lower thresholds than unilateral stimulation (and, if
so, whether the degree of facilitation is inversely related to general
olfactory ability). In this study, and well-validated single staircase
procedure was used to establish bilateral and unilateral detection
thresholds for the cranial nerve I stimulant phenyl ethyl alcohol in 130
right- and 33 left-handed subjects. No differences in sensitivity between
the left and right sides of the nose were observed in either group.
Bilateral thresholds were lower, on average, than unilateral thresholds
when the latter were categorized in terms of left and right nares. However,
the bilateral thresholds did not differ significantly from those of the
side of the nose with the lower threshold. Overall smell ability, as
measured by the University of Pennsylvania Smell Identification Test, did
not interact with any of the test measures. These data imply that (i) the
left and right sides of the nose do not systematically differ in detection
threshold sensitivity for either dextrals or sinistrals and (ii) if central
integration of left:right olfactory threshold sensitivity occurs, its
effects do not exceed the function of the better side of the nose.
相似文献
180.
Lutchen K. R.; Kaczka D. W.; Suki B.; Barnas G.; Cevenini G.; Barbini P. 《Journal of applied physiology》1993,75(6):2549-2560