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Institution

University of Georgia

EducationAthens, Georgia, United States
About: University of Georgia is a education organization based out in Athens, Georgia, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 41934 authors who have published 93622 publications receiving 3713212 citations. The organization is also known as: UGA & Franklin College.
Topics: Population, Poison control, Gene, Genome, Virus


Papers
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Journal ArticleDOI
TL;DR: It is suggested that the classical model of adaptive radiation, where morphological evolution is initially rapid and slows through time, may be rare in comparative data.
Abstract: George Gaylord Simpson famously postulated that much of life's diversity originated as adaptive radiations-more or less simultaneous divergences of numerous lines from a single ancestral adaptive type. However, identifying adaptive radiations has proven difficult due to a lack of broad-scale comparative datasets. Here, we use phylogenetic comparative data on body size and shape in a diversity of animal clades to test a key model of adaptive radiation, in which initially rapid morphological evolution is followed by relative stasis. We compared the fit of this model to both single selective peak and random walk models. We found little support for the early-burst model of adaptive radiation, whereas both other models, particularly that of selective peaks, were commonly supported. In addition, we found that the net rate of morphological evolution varied inversely with clade age. The youngest clades appear to evolve most rapidly because long-term change typically does not attain the amount of divergence predicted from rates measured over short time scales. Across our entire analysis, the dominant pattern was one of constraints shaping evolution continually through time rather than rapid evolution followed by stasis. We suggest that the classical model of adaptive radiation, where morphological evolution is initially rapid and slows through time, may be rare in comparative data.

744 citations

Journal ArticleDOI
01 Mar 2006-Obesity
TL;DR: Mechanisms explaining these adaptations are not as yet known, but metabolic and neurochemical pathways among skeletal muscle, the spinal cord, and the brain offer plausible, testable mechanisms that might help explain effects of physical activity and exercise on the central nervous system.
Abstract: Voluntary physical activity and exercise training can favorably influence brain plasticity by facilitating neurogenerative, neuroadaptive, and neuroprotective processes. At least some of the processes are mediated by neurotrophic factors. Motor skill training and regular exercise enhance executive functions of cognition and some types of learning, including motor learning in the spinal cord. These adaptations in the central nervous system have implications for the prevention and treatment of obesity, cancer, depression, the decline in cognition associated with aging, and neurological disorders such as Parkinson's disease, Alzheimer's dementia, ischemic stroke, and head and spinal cord injury. Chronic voluntary physical activity also attenuates neural responses to stress in brain circuits responsible for regulating peripheral sympathetic activity, suggesting constraint on sympathetic responses to stress that could plausibly contribute to reductions in clinical disorders such as hypertension, heart failure, oxidative stress, and suppression of immunity. Mechanisms explaining these adaptations are not as yet known, but metabolic and neurochemical pathways among skeletal muscle, the spinal cord, and the brain offer plausible, testable mechanisms that might help explain effects of physical activity and exercise on the central nervous system.

743 citations

Journal ArticleDOI
TL;DR: In this article, a high-quality draft genome sequence of the diploid P. bretschneideri Rehd was provided for de novo assembly of a highly heterozygous genome of this size with highly repetitive DNA sequences.
Abstract: Pear, the third most important temperate fruit species after grape and apple, belongs to the subfamily Pomoideae in the family Rosaceae. The majority of cultivated pears are functional diploids (2n = 34). As a popular fruit in the world market, pear has widespread cultivation on six continents, with major production in China, the United States, Italy, Argentina, and Spain (Supplemental Fig. 1). Pears are among the oldest of the world's fruit crops, with >3000 yr of cultivation history (Lombard and Westwood 1987), likely originating during the Tertiary period (65–55 million years ago [MYA]) in the mountainous regions of southwestern China and, from there, spreading on to both the East and West (Rubtsov 1944; Zeven and Zhukovsky 1975). Central Asia and eastern China are identified as two subcenters of genetic diversity for pear (Vavilov 1951). The Pyrus genus is genetically diverse with thousands of cultivars, but it can be divided into two major groups, Occidental pears (European pears) and Oriental pears (Asiatic pears). At least 22 primary species are well-recognized in Pyrus; however, only a few species, including Pyrus bretschneideri, Pyrus pyrifolia, Pyrus ussuriensis, Pyrus sinkiangensis, and Pyrus communis, have been utilized for fruit production. Herein, we report on a high-quality draft genome sequence of the diploid P. bretschneideri Rehd. cv. ‘Dangshansuli’ (also known as ‘Suli’), the most important commercial Asiatic pear cultivar grown in the world (>4 million tons per year), having >500 yr of cultivated history in China. Pear is highly heterozygous due to self-incompatibility and interspecies compatibility. The genome is known to have an abundance of repetitive DNA sequences. In this study, a novel combination of BAC-by-BAC (bacterial artificial chromosome) strategy, with Illumina sequencing technology, is used for the first time for de novo assembly of a highly heterozygous genome of this size with highly repetitive DNA sequences. This has demonstrated that a complex plant genome sequence can be assembled and characterized using these technologies without the availability of a physical reference. Additionally, we also report on primary factors contributing to genome size differences between pear and apple, both belonging to the subfamily Pomoideae; chromosomal evolution of Rosaceae; and genes controlling valuable traits of pear, including self-incompatibility, lignified stone cells in flesh of fruit (unique to pear), sugar, and aroma.

742 citations

Journal ArticleDOI
TL;DR: This reference genome sequence will facilitate the identification of the genetic basis of agronomically important traits, and accelerate the development of improved pigeonpea varieties that could improve food security in many developing countries.
Abstract: Pigeonpea is an important legume food crop grown primarily by smallholder farmers in many semi-arid tropical regions of the world. We used the Illumina next-generation sequencing platform to generate 237.2 Gb of sequence, which along with Sanger-based bacterial artificial chromosome end sequences and a genetic map, we assembled into scaffolds representing 72.7% (605.78 Mb) of the 833.07 Mb pigeonpea genome. Genome analysis predicted 48,680 genes for pigeonpea and also showed the potential role that certain gene families, for example, drought tolerance-related genes, have played throughout the domestication of pigeonpea and the evolution of its ancestors. Although we found a few segmental duplication events, we did not observe the recent genome-wide duplication events observed in soybean. This reference genome sequence will facilitate the identification of the genetic basis of agronomically important traits, and accelerate the development of improved pigeonpea varieties that could improve food security in many developing countries.

741 citations

Journal ArticleDOI
TL;DR: A method for generating gene replacements and deletions in Escherichia coli using a temperature-sensitive pSC101 replicon to facilitate the gene replacement and can be used to generate deletions of essential genes.
Abstract: We describe a method for generating gene replacements and deletions in Escherichia coli. The technique is simple and rapid and can be applied to most genes, even those that are essential. What makes this method unique and particularly effective is the use of a temperature-sensitive pSC101 replicon to facilitate the gene replacement. The method proceeds by homologous recombination between a gene on the chromosome and homologous sequences carried on a plasmid temperature sensitive for DNA replication. Thus, after transformation of the plasmid into an appropriate host, it is possible to select for integration of the plasmid into the chromosome at 44 degrees C. Subsequent growth of these cointegrates at 30 degrees C leads to a second recombination event, resulting in their resolution. Depending on where the second recombination event takes place, the chromosome will either have undergone a gene replacement or retain the original copy of the gene. The procedure can also be used to effect the transfer of an allele from a plasmid to the chromosome or to rescue a chromosomal allele onto a plasmid. Since the resolved plasmid can be maintained by selection, this technique can be used to generate deletions of essential genes.

740 citations


Authors

Showing all 42268 results

NameH-indexPapersCitations
Rob Knight2011061253207
Feng Zhang1721278181865
Zhenan Bao169865106571
Carl W. Cotman165809105323
Yoshio Bando147123480883
Mark Raymond Adams1471187135038
Han Zhang13097058863
Dmitri Golberg129102461788
Godfrey D. Pearlson12874058845
Douglas E. Soltis12761267161
Richard A. Dixon12660371424
Ajit Varki12454258772
Keith A. Johnson12079851034
Gustavo E. Scuseria12065895195
Julian I. Schroeder12031550323
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
2023125
2022542
20214,670
20204,504
20194,098
20183,994