scholarly journals Multiple losses of flight and recent speciation in steamer ducks

2012 ◽  
Vol 279 (1737) ◽  
pp. 2339-2346 ◽  
Author(s):  
Tara L. Fulton ◽  
Brandon Letts ◽  
Beth Shapiro
Keyword(s):  
Common Ancestor ◽  
Falkland Islands ◽  
Land Bridge ◽  
Separate Species ◽  
Duck Species ◽  
Traditional Classification ◽  
Distinct Lineage ◽  
Insular Population ◽  
Glacial Advance

Steamer ducks ( Tachyeres ) comprise four species, three of which are flightless. The flightless species are believed to have diverged from a flying common ancestor during the Late Pleistocene; however, their taxonomy remains contentious. Of particular interest is the previously unstudied population of flying steamer ducks in the Falkland Islands. We present the first genetic data from this insular population, and illustrate that the flying and flightless steamer ducks on the Falkland Islands are genetically indistinguishable, in contrast to their traditional classification as separate species. The three species that reside in continental South America form a genetically distinct lineage from the Falkland Island ducks. The Falkland steamer ducks diverged from their continental relatives 2.2–0.6 million years ago, coincident with a probable land bridge connecting the Falkland Islands to the mainland. The three continental species share a common ancestor approximately 15 000 years ago, possibly owing to isolation during a recent glacial advance. The continental steamer duck species are not reciprocally monophyletic, but show some amount of genetic differentiation between them. Each lineage of Tachyeres represents a different stage between flight and flightlessness. Their phylogenetic relationships suggest multiple losses of flight and/or long-term persistence of mixed-flight capability. As such, steamer ducks may provide a model system to study the evolution of flightlessness.

Periodic monitoring of vampire bats and rabies: a new framework for animal restoration projects in the Neotropics

2020 ◽  
Author(s):  
Fernando Gonçalves ◽  
Daniel G. Streicker ◽  
Mauro Galetti
Keyword(s):  
Disease Transmission ◽  
Lessons Learned ◽  
Multidisciplinary Teams ◽  
Risk Area ◽  
Food Web Structure ◽  
Land Bridge ◽  
High Risk Area ◽  
Restoration Project ◽  
Vampire Bats

Nowadays, restoration project might lead to increased public engagement and enthusiasm for biodiversity and is receiving increased media attention in major newspapers, TED talks and the scientific literature. However, empirical research on restoration project is rare, fragmented, and geographically biased and long-term studies that monitor indirect and unexpected effects are needed to support future management decisions especially in the Neotropical area. Changes in animal population dynamics and community composition following species (re)introduction may have unanticipated consequences for a variety of downstream ecosystem processes, including food web structure, predator-prey systems and infectious disease transmission. Recently, an unprecedented study in Brazil showed changes in vampire bat feeding following a rewilding project and further transformed the land-bridge island into a high-risk area for rabies transmission. Due the lessons learned from ongoing project, we present a novel approach on how to anticipate, monitor, and mitigate the vampire bats and rabies in rewilding projects. We pinpoint a series of precautions and the need for long-term monitoring of vampire bats and rabies responses to rewilding projects and highlighted the importance of multidisciplinary teams of scientist and managers focusing on prevention educational program of rabies risk transmitted by bats. In addition, monitoring the relative abundance of vampire bats, considering reproductive control by sterilization and oral vaccines that autonomously transfer among bats would reduce the probability, size and duration of rabies outbreaks. The rewilding assessment framework presented here responds to calls to better integrate the science and practice of rewilding and also could be used for long-term studying of bat-transmitted pathogen in the Neotropical area as the region is considered a geographic hotspots of “missing bat zoonoses”.

scholarly journals Long-Term Experimental Evolution in Escherichia coli. IV. Targets of Selection and the Specificity of Adaptation

Genetics ◽  
1996 ◽  
Vol 143 (1) ◽  
pp. 15-26 ◽  
Author(s):  
Michael Travisano ◽  
Richard E Lenski
Keyword(s):  
Escherichia Coli ◽  
Experimental Evolution ◽  
Common Ancestor ◽  
The Novel ◽  
Physiological Mechanisms ◽  
Outer Membranes ◽  
Limiting Nutrient ◽  
Novel Environments ◽  
Uptake Mechanisms

Abstract This study investigates the physiological manifestation of adaptive evolutionary change in 12 replicate populations of Escherichia coli that were propagated for 2000 generations in a glucose-limited environment. Representative genotypes from each population were assayed for fitness relative to their common ancestor in the experimental glucose environment and in 11 novel single-nutrient environments. After 2000 generations, the 12 derived genotypes had diverged into at least six distinct phenotypic classes. The nutrients were classified into four groups based upon their uptake physiology. All 12 derived genotypes improved in fitness by similar amounts in the glucose environment, and this pattern of parallel fitness gains was also seen in those novel environments where the limiting nutrient shared uptake mechanisms with glucose. Fitness showed little or no consistent improvement, but much greater genetic variation, in novel environments where the limiting nutrient differed from glucose in its uptake mechanisms. This pattern of fitness variation in the novel nutrient environments suggests that the independently derived genotypes adapted to the glucose environment by similar, but not identical, changes in the physiological mechanisms for moving glucose across both the inner and outer membranes.

Introgression between non-sister species of honeyeaters (Aves: Meliphagidae) several million years after speciation

2019 ◽  
Vol 128 (3) ◽  
pp. 583-591
Author(s):  
Leo Joseph ◽  
Alex Drew ◽  
Ian J Mason ◽  
Jeffrey L Peters
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Sex Chromosomes ◽  
Common Ancestor ◽  
Sister Species ◽  
Species Boundaries ◽  
North Eastern ◽  
The City

Abstract We reassessed whether two parapatric non-sister Australian honeyeater species (Aves: Meliphagidae), varied and mangrove honeyeaters (Gavicalis versicolor and G. fasciogularis, respectively), that diverged from a common ancestor c. 2.5 Mya intergrade in the Townsville area of north-eastern Queensland. Consistent with a previous specimen-based study, by using genomics methods we show one-way gene flow for autosomal but not Z-linked markers from varied into mangrove honeyeaters. Introgression barely extends south of the area of parapatry in and around the city of Townsville. While demonstrating the long-term porosity of species boundaries over several million years, our data also suggest a clear role of sex chromosomes in maintaining reproductive isolation.

scholarly journals Long-term trends in gale days and storminess for the Falkland Islands

2015 ◽  
Vol 36 (3) ◽  
pp. 1413-1427 ◽  
Author(s):  
Philip D. Jones ◽  
Colin Harpham ◽  
David Lister
Keyword(s):  
Falkland Islands ◽  
Long Term Trends

scholarly journals Fauna of gamasina mites (Gamasoidea) of small mammals of a natural region «Samarskaya Luka»

2016 ◽  
Vol 5 (2) ◽  
pp. 57-63
Author(s):  
Irina Anatol’evna Sorokopud
Keyword(s):  
Small Mammals ◽  
Water Vole ◽  
Separate Species ◽  
Natural Region ◽  
Mole Vole ◽  
Ecological Complex ◽  
Tundra Vole ◽  
First Time ◽  
Samarskaya Luka

Data on fauna of gamasina mites parasitizing on small mammals are provided in article. Data are obtained during long-term monitoring of an ecological complex of small mammals of a natural and territorial complex Samarskaya Luka, which is realized since 1999. Also data on fauna of gamasina mites in 14 years of researches (2000-2003, 2005, 2007-2015 years), including literary data about the gamasina mites of this territory, are generalized and analysed. Specific accessory of 7439 individuals of mites, seven childbirth of three families relating to fifteen types is defined. Parasitizing the gamasina mites on 16 species of small mammals, including groups rodents, soricomorpha, carnivora (least weasel) is established. Domination of separate species of mites is revealed, so to eudominant Laelaps hilaris and Hirstionyssus isabellinus are belong, dominants are - Hirstionyssus ellobii , Haemolaelaps glasgowi , Hyperlaelaps arvalis , L. agilis . Myonyssus rossicus , L. algericus , Haemogamasus ambulans and Hirstionyssus macedonicus were extremely rare species met in single copies. For the first time for this territory types of H. ellobii , L. micromydis , H. ambulans , H. macedonicus are noted. Conclusions on degree of a confinedness of parasites to certain types of hosts are drawn. Monohostal types: L. agilis (the host - a yellow-necked mouse), L. muris (the host - a tundra vole and a water vole), L. micromydis (the host - a small mouse), L. algericus (the host - a house mouse), H. arvalis (the host - a tundra vole and a water vole), H. ellobii (the host - a northern mole vole). Polihostal: H. musculi , L. hilaris , H. isabellinus , H. glasgowi , E. stabularis , H. nidi .

scholarly journals Procr-expressing progenitor cells are responsible for murine ovulatory rupture repair of ovarian surface epithelium

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Jingqiang Wang ◽  
Daisong Wang ◽  
Kun Chu ◽  
Wen Li ◽  
Yi Arial Zeng
Keyword(s):  
Progenitor Cells ◽  
Adult Stem Cells ◽  
Ovarian Surface Epithelium ◽  
Lineage Tracing ◽  
Surface Epithelium ◽  
Ovarian Surface ◽  
Adult Mice ◽  
Distinct Lineage ◽  
Expansion System

Abstract Ovarian surface epithelium (OSE) undergoes recurring ovulatory rupture and repair. The OSE replenishing mechanism post ovulation remains unclear. Here we report that the expression of Protein C Receptor (Procr) marks a progenitor population in adult mice that is responsible for OSE repair post ovulation. Procr+  cells are the major cell source for OSE repair. The mechanism facilitating the rapid re-epithelialization is through the immediate expansion of Procr+  cells upon OSE rupture. Targeted ablation of Procr+  cells impedes the repairing process. Moreover, Procr+  cells displayed robust colony-formation capacity in culture, which we harnessed and established a long-term culture and expansion system of OSE cells. Finally, we show that Procr+  cells and previously reported Lgr5+ cells have distinct lineage tracing behavior in OSE homeostasis. Our study suggests that Procr marks progenitor cells that are critical for OSE ovulatory rupture and homeostasis, providing insight into how adult stem cells respond upon injury.

A new species of chameleon (Squamata: Chamaeleonidae) from the Aberdare Mountains in the central highlands of Kenya

Zootaxa ◽  
2012 ◽  
Vol 3391 (1) ◽  
pp. 1 ◽  
Author(s):  
JAN STIPALA ◽  
NICOLA LUTZMANN ◽  
PATRICK K. MALONZA ◽  
PAUL WILKINSON ◽  
BRENDAN GODLEY ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
New Species ◽  
Temporal Region ◽  
New Taxon ◽  
Term Survival ◽  
Long Term Survival ◽  
Distinct Lineage ◽  
Central Highlands ◽  
A New Species

We describe a new species of chameleon, Trioceros kinangopensis sp. nov., from Kinangop Peak in the Aberdare moun-tains, central highlands of Kenya. The proposed new species is morphologically and genetically distinct from other mem-ber of the bitaeniatus-group. It is morphologically most similar to T. schubotzi but differs in the lack of sexual sizedimorphism, smaller-sized females, smoother, less angular canthus rostrales, smaller scales on the temporal region and abright orange gular crest in males. Mitochondrial DNA indicates that the proposed new taxon is a distinct lineage that isclosely related to T. nyirit and T. schubotzi. The distribution of T. kinangopensis sp. nov. appears to be restricted to the afroalpine zone in vicintiy of Kinangop Peak and fires may pose a serious threat to the long-term survival of this species.

Problems in Zoogeography of the Lake Trout, Salvelinus namaycush

1964 ◽  
Vol 21 (5) ◽  
pp. 977-994 ◽  
Author(s):  
C. C. Lindsey
Keyword(s):  
New England ◽  
Lake Trout ◽  
Ecological Factors ◽  
Wide Distribution ◽  
Bering Strait ◽  
Land Bridge ◽  
Bering Land Bridge ◽  
Water Courses ◽  
Hucho Taimen ◽  
Glacial Advance

Disagreement exists in the literature as to whether lake trout survived Wisconsin glaciation north or south of the ice sheet. Other freshwater fishes whose range in North America equals or exceeds that of lake trout all survived in both northern and southern refugia. Arguments in favour of a southern refugium for lake trout include their wide distribution eastward to Nova Scotia and New England, their presence in some Mississippi headwaters, and possible late-Wisconsin date of a fossil lake trout south of glaciation. Absence from some habitable lakes along the southern margin of glaciation is attributable to northward shift of isotherms during the hypsithermal period. A northern refugium is suggested by occurrence of lake trout in remote parts of Alaska, and the improbability of their having failed to reach and persist in Alaska prior to last glacial advance. They do not now closely approach Bering Strait, and may be held in check by ecological factors which have been operative also during previous glacial and interglacial periods, on the Bering land bridge as well as on the continent. Hucho taimen is a related Asian counterpart whose dispersal may be similarly controlled. Large lampreys may prevent dispersal of lake trout into lower water courses and the sea.

scholarly journals A shift in aggregation avoidance strategy marks a long-term direction to protein evolution

2017 ◽  
Author(s):  
S.G. Foy ◽  
B.A. Wilson ◽  
J. Bertram ◽  
M.H.J. Cordes ◽  
J. Masel
Keyword(s):  
Amino Acids ◽  
Common Ancestor ◽  
Gene Families ◽  
Protein Coding ◽  
Hydrophobic Residues ◽  
Extant Species ◽  
Aggregation Problem ◽  
Hydrophobic Amino Acids ◽  
Ancestral States

AbstractTo detect a direction to evolution, without the pitfalls of reconstructing ancestral states, we need to compare “more evolved” to “less evolved” entities. But because all extant species have the same common ancestor, none are chronologically more evolved than any other. However, different gene families were born at different times, allowing us to compare young protein-coding genes to those that are older and hence have been evolving for longer. To be retained during evolution, a protein must not only have a function, but must also avoid toxic dysfunction such as protein aggregation. There is conflict between the two requirements; hydrophobic amino acids form the cores of protein folds, but also promote aggregation. Young genes avoid strongly hydrophobic amino acids, which is presumably the simplest solution to the aggregation problem. Here we show that young genes’ few hydrophobic residues are clustered near one another along the primary sequence, presumably to assist folding. The higher aggregation risk created by the higher hydrophobicity of older genes is counteracted by more subtle effects in the ordering of the amino acids, including a reduction in the clustering of hydrophobic residues until they eventually become more interspersed than if distributed randomly. This interspersion has previously been reported to be a general property of proteins, but here we find that it is restricted to old genes. Quantitatively, the index of dispersion delineates a gradual trend, i.e. a decrease in the clustering of hydrophobic amino acids over billions of years.

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