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101.
SARAH C. CREWS ROSEMARY G. GILLESPIE 《Biological journal of the Linnean Society. Linnean Society of London》2010,101(2):288-322
The Caribbean region includes a geologically complex mix of islands, which have served as a backdrop for some significant studies of biogeography, mostly with vertebrates. Here, we use the tropical/subtropical spider genus Selenops (Selenopidae) to obtain a finer resolution of the role of geology in shaping patterns of species diversity. We obtained a broad geographic sample from over 200 localities from both the islands and American mainland. DNA sequence data were generated for three mitochondrial genes and one nuclear gene for eleven outgroup taxa and nearly 60 selenopid species. Phylogenetic analysis of the data revealed several biogeographic patterns common to other lineages that have diversified in the region, the most significant being: (1) a distinct biogeographic break between Northern and Southern Lesser Antilles, although with a slight shift in the location of the disjunction; (2) diversification within the islands of Jamaica and Hispaniola; (3) higher diversity of species in the Greater Antilles relative to the Lesser Antilles. However, a strikingly unique pattern in Caribbean Selenops is that Cuban species are not basal in the Caribbean clade. Analyses to test competing hypotheses of vicariance and dispersal support colonization through GAARlandia, an Eocene–Oligocene land span extending from South America to the Greater Antilles, rather than over‐water dispersal. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 288–322. 相似文献
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104.
MICHAEL K. SCHWARTZ KEITH B. AUBRY KEVIN S. MCKELVEY KRISTINE L. PILGRIM JEFFREY P. COPELAND JOHN R. SQUIRES ROBERT M. INMAN SAMANTHA M. WISELY LEONARD F. RUGGIERO 《The Journal of wildlife management》2007,71(7):2170-2179
ABSTRACT Delineating a species' geographic range using the spatial distribution of museum specimens or even contemporary detection-non-detection data can be difficult. This is particularly true at the periphery of a species range where species' distributions are often disjunct. Wolverines (Gulo gulo) are wide-ranging mammals with discontinuous and potentially isolated populations at the periphery of their range. One potentially disjunct population occurred in the Sierra Nevada Mountains, California, USA, and appears to have been extirpated by the 1930s. Many early 20th century naturalists believed that this population was connected to other populations occurring in the Cascade Range of northern California, Oregon, and Washington, USA, but a recent analysis of historical records suggests that California wolverines were isolated from other populations in North America. We used DNA extracted from museum specimens to examine whether California wolverines were isolated. Both nuclear and mitochondrial DNA data indicate that California wolverines were genetically distinct from extant populations, suggesting long-term isolation. We identified 2 new control region (mitochondrial DNA) haplotypes located only within California. We used these data and referenced sequences from the Rocky Mountains, USA, to make inferences regarding potential wolverine translocations into California. In addition, we used these genetic data to make inferences about wolverine conservation throughout western North America. 相似文献
105.
Contemporary evolution of secondary sexual traits in the wild 总被引:2,自引:0,他引:2
106.
Reiner-Benaim A 《Biometrical journal. Biometrische Zeitschrift》2007,49(1):107-126
The multiple testing problem attributed to gene expression analysis is challenging not only by its size, but also by possible dependence between the expression levels of different genes resulting from coregulations of the genes. Furthermore, the measurement errors of these expression levels may be dependent as well since they are subjected to several technical factors. Multiple testing of such data faces the challenge of correlated test statistics. In such a case, the control of the False Discovery Rate (FDR) is not straightforward, and thus demands new approaches and solutions that will address multiplicity while accounting for this dependency. This paper investigates the effects of dependency between bormal test statistics on FDR control in two-sided testing, using the linear step-up procedure (BH) of Benjamini and Hochberg (1995). The case of two multiple hypotheses is examined first. A simulation study offers primary insight into the behavior of the FDR subjected to different levels of correlation and distance between null and alternative means. A theoretical analysis follows in order to obtain explicit upper bounds to the FDR. These results are then extended to more than two multiple tests, thereby offering a better perspective on the effect of the proportion of false null hypotheses, as well as the structure of the test statistics correlation matrix. An example from gene expression data analysis is presented. 相似文献
107.
采用RAPD技术测定分析了河北省皱大球蚧和瘤坚大球蚧8个地理种群的遗传结构。结果表明:5种引物在8个种群中共产生了65条RAPD标记,各地理种群之间没有产生各自的特征标记;不同种群间的遗传相似程度与其地理间距呈反比;种群内的遗传相似程度比种间高。Shannon信息指数表明,皱大球蚧的平均遗传多样性高于瘤坚大球蚧,分别为0.3456和0.3225说明物种不同,其变异程度也不同。 相似文献
108.
Bergmann's rule predicts larger body sizes in species living in higher latitudes and altitudes. This rule appears to be valid for endotherms, but its relevance to ectotherm vertebrates has largely been debated. In squamate reptiles (lizards and snakes), only one study, based on Liolaemus species of the boulengeri clade, has provided phylogenetic evidence in favour of Bergmann's clines. We reassessed this model in the same lizard clade, using a more representative measure of species body size and including a larger number of taxa in the sample. We found no evidence to support Bergmann's rule in this lineage. However, these non-significant results appear to be explained only by the inclusion of further species rather than by a different estimation of body size. Analyses conducted on the 16 species included in the previous study always revealed significant relationships between body size and latitude-altitude, whereas, the enlarged sample always rejected the pattern predicted by Bergmann's rule. 相似文献
109.
H. J. B. Birks 《Vegetation History and Archaeobotany》2007,16(2-3):197-202
Detrended canonical correspondence analysis is used to estimate the amount of palynological change or compositional turnover
in ten Holocene pollen-stratigraphical sequences from Setesdal, southern Norway. The results, when the analyses are standardised
for the same time interval, show that the highest amounts of change occurred at sites in the south of Setesdal where there
is a richer tree flora. This primarily methodological study provides a robust approach to answering the question as to how
much change is recorded within a pollen sequence, and to summarising the amount of change between sequences. 相似文献
110.
A key issue in ecosystem management in the western U.S. is the determination of the historic range of variability of fire
and its ecological significance prior to major land-use changes associated with Euro-American settlement. The present study
relates spatial variation in historical fire occurrence to variation in abiotic and biotic predictors of fire frequency and
severity across the elevational range of ponderosa pine in northern Colorado. Logistic regression was used to relate fire
frequency to environmental predictors and to derive a probability surface for mapping purposes. These results indicate that
less than 20% of the ponderosa pine zone had an historic fire regime (pre-1915) of relatively frequent fires (mean fire intervals,
MFI, <30 years). More than 80% is reconstructed to have had a lower frequency (MFI ≥ 30 years), more variable severity fire
regime. High fire frequency is clearly associated with low elevations. Lower and more variable fire frequencies, associated
with high and moderate severities, occur across a broad range of elevation and are related to variations in other environmental
variables. Only a small part of the ponderosa pine zone fits the widespread view that the historic fire regime was characterized
mainly by frequent, low-severity that maintained open conditions. Management attempts to restore historic forest structures
and/or fire conditions must recognize that infrequent severe fires were an important component of the historic fire regime
in this cover type in northern Colorado. 相似文献