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Extant timetrees are consistent with a myriad of diversification histories 期刊论文
NATURE, 2020, 580 (7804) : 502-+
作者:  Bhaskar, M. K.;  Riedinger, R.;  Machielse, B.;  Levonian, D. S.;  Nguyen, C. T.;  Knall, E. N.;  Park, H.;  Englund, D.;  Loncar, M.;  Sukachev, D. D.;  Lukin, M. D.
收藏  |  浏览/下载:39/0  |  提交时间:2020/07/03

An infinite number of alternative diversification scenarios-which may have markedly different, but equally plausible, dynamics-can underpin a given time-calibrated phylogeny of extant species, suggesting many previous studies have over-interpreted phylogenetic evidence.


Time-calibrated phylogenies of extant species (referred to here as '  extant timetrees'  ) are widely used for estimating diversification dynamics(1). However, there has been considerable debate surrounding the reliability of these inferences(2-5) and, to date, this critical question remains unresolved. Here we clarify the precise information that can be extracted from extant timetrees under the generalized birth-death model, which underlies most existing methods of estimation. We prove that, for any diversification scenario, there exists an infinite number of alternative diversification scenarios that are equally likely to have generated any given extant timetree. These '  congruent'  scenarios cannot possibly be distinguished using extant timetrees alone, even in the presence of infinite data. Importantly, congruent diversification scenarios can exhibit markedly different and yet similarly plausible dynamics, which suggests that many previous studies may have over-interpreted phylogenetic evidence. We introduce identifiable and easily interpretable variables that contain all available information about past diversification dynamics, and demonstrate that these can be estimated from extant timetrees. We suggest that measuring and modelling these identifiable variables offers a more robust way to study historical diversification dynamics. Our findings also make it clear that palaeontological data will continue to be crucial for answering some macroevolutionary questions.


  
Ancient West African foragers in the context of African population history 期刊论文
NATURE, 2020, 577 (7792) : 665-+
作者:  Grunwald, Hannah A.;  Gantz, Valentino M.;  Poplawski, Gunnar;  Xu, Xiang-Ru S.;  Bier, Ethan;  Cooper, Kimberly L.
收藏  |  浏览/下载:46/0  |  提交时间:2020/07/03

Genome-wide ancestry profiles of four individuals, dating to 8,000 and 3,000 years before present, from the archaeological site of Shum Laka (Cameroon) shed light on the deep population history of sub-Saharan Africa.


Our knowledge of ancient human population structure in sub-Saharan Africa, particularly prior to the advent of food production, remains limited. Here we report genome-wide DNA data from four children-two of whom were buried approximately 8,000 years ago and two 3,000 years ago-from Shum Laka (Cameroon), one of the earliest known archaeological sites within the probable homeland of the Bantu language group(1-11). One individual carried the deeply divergent Y chromosome haplogroup A00, which today is found almost exclusively in the same region(12,13). However, the genome-wide ancestry profiles of all four individuals are most similar to those of present-day hunter-gatherers from western Central Africa, which implies that populations in western Cameroon today-as well as speakers of Bantu languages from across the continent-are not descended substantially from the population represented by these four people. We infer an Africa-wide phylogeny that features widespread admixture and three prominent radiations, including one that gave rise to at least four major lineages deep in the history of modern humans.


  
Evolution-guided discovery of antibiotics that inhibit peptidoglycan remodelling 期刊论文
NATURE, 2020, 578 (7796) : 582-+
作者:  Faraco, Giuseppe;  Hochrainer, Karin;  Segarra, Steven G.;  Schaeffer, Samantha;  Santisteban, Monica M.;  Menon, Ajay;  Jiang, Hong;  Holtzman, David M.;  Anrather, Josef;  Iadecola, Costantino
收藏  |  浏览/下载:47/0  |  提交时间:2020/07/03

Addressing the ongoing antibiotic crisis requires the discovery of compounds with novel mechanisms of action that are capable of treating drug-resistant infections(1). Many antibiotics are sourced from specialized metabolites produced by bacteria, particularly those of the Actinomycetes family(2). Although actinomycete extracts have traditionally been screened using activity-based platforms, this approach has become unfavourable owing to the frequent rediscovery of known compounds. Genome sequencing of actinomycetes reveals an untapped reservoir of biosynthetic gene clusters, but prioritization is required to predict which gene clusters may yield promising new chemical matter(2). Here we make use of the phylogeny of biosynthetic genes along with the lack of known resistance determinants to predict divergent members of the glycopeptide family of antibiotics that are likely to possess new biological activities. Using these predictions, we uncovered two members of a new functional class of glycopeptide antibiotics-the known glycopeptide antibiotic complestatin and a newly discovered compound we call corbomycin-that have a novel mode of action. We show that by binding to peptidoglycan, complestatin and corbomycin block the action of autolysins-essential peptidoglycan hydrolases that are required for remodelling of the cell wall during growth. Corbomycin and complestatin have low levels of resistance development and are effective in reducing bacterial burden in a mouse model of skin MRSA infection.


The glycopeptide antibiotic-related compounds complestatin and corbomycin function by binding to peptidoglycan and blocking the action of autolysins-peptidoglycan hydrolase enzymes that remodel the cell wall during growth.


  
Diverging phenological responses of Arctic seabirds to an earlier spring 期刊论文
GLOBAL CHANGE BIOLOGY, 2019
作者:  Descamps, Sebastien;  Ramirez, Francisco;  Benjaminsen, Sigurd;  Anker-Nilssen, Tycho;  Barrett, Robert T.;  Burr, Zofia;  Christensen-Dalsgaard, Signe;  Erikstad, Kjell-Einar;  Irons, David B.;  Lorentsen, Svein-Hakon;  Mallory, Mark L.;  Robertson, Gregory J.;  Reiertsen, Tone Kirstin;  Strom, Hallvard;  Varpe, Oystein;  Lavergne, Sebastien
收藏  |  浏览/下载:30/0  |  提交时间:2019/11/27
breeding phenology  climate warming  foraging strategy  phylogeny  spring onset  
Testing Darwin's transoceanic dispersal hypothesis for the inland nettle family (Urticaceae) 期刊论文
ECOLOGY LETTERS, 2018, 21 (10) : 1515-1529
作者:  Wu, Zeng-Yuan;  Liu, Jie;  Provan, Jim;  Wang, Hong;  Chen, Chia-Jui;  Cadotte, Marc W.;  Luo, Ya-Huang;  Amorim, Bruno S.;  Li, De-Zhu;  Milne, Richard I.
收藏  |  浏览/下载:25/0  |  提交时间:2019/04/09
Biogeography  ecological traits  long-distance dispersal  molecular phylogeny  ocean current  seed viability  Urticaceae  
C-4 photosynthesis evolved in warm climates but promoted migration to cooler ones 期刊论文
ECOLOGY LETTERS, 2018, 21 (3) : 376-383
作者:  Watcharamongkol, Teera;  Christin, Pascal-Antoine;  Osborne, Colin P.
收藏  |  浏览/下载:16/0  |  提交时间:2019/04/09
Adaptation  C-4 photosynthesis  climate  evolution  phylogeny  temperature niche  
Early Paleocene landbird supports rapid phylogenetic and morphological diversification of crown birds after the K-Pg mass extinction 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2017, 114 (30) : 8047-8052
作者:  Ksepka, Daniel T.;  Stidham, Thomas A.;  Williamson, Thomas E.
收藏  |  浏览/下载:9/0  |  提交时间:2019/11/27
aves  phylogeny  morphology  fossil  evolution