Three evolutionarily significant units for conservation in the iguanid genus Brachylophus

2006 ◽  
Vol 12 (1) ◽  
pp. 64
Author(s):  
Emma L. Burns ◽  
Brian H. Costello ◽  
Bronwyn A. Houlden
Keyword(s):  
Pacific Islands ◽  
Phylogenetic Analyses ◽  
Sequence Divergence ◽  
Conservation Priorities ◽  
Separate Species ◽  
Island Populations ◽  
Evolutionarily Significant Units ◽  
Average Sequence Divergence ◽  
History Of ◽  
South Pacific Islands

We examined phylogenetic relationships within the genus Brachylophus, which comprises two endangered iguana species endemic to the South Pacific islands of Fiji and Tonga. Genetic variation among Fijian Crested Iguanas B. vitiensis and Fijian and Tongan Banded Iguanas B. fasciatus was analysed using mitochondrial DNA (mtDNA) cytochrome b (cyt b) characterized from 35 individuals from island populations. Three distinct clades of Brachylophus were identified. The most divergent clade comprised B. fasciatus from Tonga, which supports the recognition of Tongan iguanas as a separate species. Molecular clock estimates suggested that the average sequence divergence (6.4%) between Tongan and Fijian B. fasciatus clades equated to 7 - 15.8 MY of separation, confirming that extant Brachylophus species have a long history of evolution in situ in the Fijian and Tongan archipelago. Phylogenetic analyses also revealed that Fijian B. fasciatus and B. vitiensis iguana populations were not reciprocally monophyletic. One clade comprised two mtDNA haplotypes from the Fijian islands of Monu, Monuriki, Devuilau, Waya and Yadua Taba. The other clade comprised B. fasciatus haplotypes from Kadavu and Gau, which was divergent from both the aforementioned Fijian clade (dA = 3.5%), and the Tongan clade (dA = 6.4%). In addition to mtDNA data, variation was assessed at microsatellite loci, and significant differentiation between iguana populations was detected. Based on both mtDNA and microsatellite analysis, the conservation priorities for these endangered lizards must be reassessed to protect iguanas as three distinct evolutionarily significant units.

scholarly journals Molecular Systematics and Biogeography of Antillean Thrashers, Tremblers, and Mockingbirds (Aves: Mimidae)

The Auk ◽  
2001 ◽  
Vol 118 (1) ◽  
pp. 35-55 ◽  
Author(s):  
Jeffrey S. Hunt ◽  
Eldredge Bermingham ◽  
Robert E. Ricklefs
Keyword(s):  
Mitochondrial Dna ◽  
Phylogenetic Analyses ◽  
Strong Support ◽  
Sequence Divergence ◽  
The West ◽  
Island Populations ◽  
Mimus Polyglottos ◽  
History Of ◽  
Dumetella Carolinensis ◽  
Phylogenetic Hypotheses

Abstract We constructed phylogenetic hypotheses for Greater and Lesser Antillean Mimidae, including five endemic species of tremblers and thrashers that represent the best plausible example of an avian radiation within the Lesser Antilles. Phylogenetic relationships were inferred from analysis of 3,491 base pairs (bp) of mitochondrial DNA (mtDNA) and roughly 780 bp of the nuclear-encoded myoglobin gene. We used a subset of mtDNA gene sequences and pcrRFLP analysis to evaluate the phylogeographic relationships among individuals representing island populations of the Brown and Gray tremblers (Cinclocerthia ruficauda and C. gutturalis), Pearly-eyed Thrasher (Margarops fuscatus), Scaly-breasted Thrasher (Margarops fuscus), and Antillean and continental populations of the Tropical (Mimus gilvus) and Northern mockingbirds (Mimus polyglottos). Phylogeographic analysis distinguished three strongly differentiated mtDNA clades among tremblers, as well as distinct southern (St. Lucia and Martinique) and northern (Dominica to Montserrat) mtDNA lineages of the Scaly-breasted Thrasher. Minor geographic subdivision was also observed between continental and Antillean populations of the Tropical Mockingbird. Phylogenetic analyses of species-level Mimidae relationships that are based on mtDNA and nuclear sequences provide strong support for the monophyly and Antillean origin of a clade that consists of the tremblers, Pearly-eyed Thrasher, and Scaly-breasted Thrasher, but reject the monophyly of the genus Margarops. Phylogenetic analysis cannot confirm the monophyly of all endemic Antillean mimids because of the apparently contemporaneous diversification of the Antillean White-breasted Thrasher (Ramphocinclus brachyurus) with the continental Gray Catbird (Dumetella carolinensis) and Black Catbird (Melanoptila glabrirostris). However, an insertion and a deletion in the myoglobin intron 2 sequence support grouping the West Indian thrashers and tremblers, from which we infer that the endemic Lesser Antillean mimids are an indigenous radiation. Assuming a constant mtDNA clock for the Mimidae, the splitting of the Northern and Tropical mockingbird lineages is roughly contemporaneous with the separation of the three trembler clades, as well as the two Scaly-breasted Thrasher clades. Application of a mitochondrial DNA clock ticking at 2% sequence divergence per million years (Ma), suggests that the history of the endemic thrasher and trembler lineage in the West Indies extends back about 4 Ma, and the three distinct clades of tremblers split about 2 Ma ago.

scholarly journals Whole genome sequences of Malawi cichlids reveal multiple radiations interconnected by gene flow

2017 ◽  
Author(s):  
Milan Malinsky ◽  
Hannes Svardal ◽  
Alexandra M. Tyers ◽  
Eric A. Miska ◽  
Martin J. Genner ◽  
...  
Keyword(s):  
Gene Flow ◽  
Fish Species ◽  
Phylogenetic Analyses ◽  
Cichlid Fish ◽  
Sequence Divergence ◽  
Single Species ◽  
Lake Malawi ◽  
Genomic Diversity ◽  
Average Sequence Divergence ◽  
Deep Water Species

AbstractThe hundreds of cichlid fish species in Lake Malawi constitute the most extensive recent vertebrate adaptive radiation. Here we characterize its genomic diversity by sequencing 134 individuals covering 73 species across all major lineages. Average sequence divergence between species pairs is only 0.1-0.25%. These divergence values overlap diversity within species, with 82% of heterozygosity shared between species. Phylogenetic analyses suggest that diversification initially proceeded by serial branching from a generalistAstatotilapia-likeancestor. However, no single species tree adequately represents all species relationships, with evidence for substantial gene flow at multiple times. Common signatures of selection on visual and oxygen transport genes shared by distantly related deep water species point to both adaptive introgression and independent selection. These findings enhance our understanding of genomic processes underlying rapid species diversification, and provide a platform for future genetic analysis of the Malawi radiation.One Sentence Summary: The genomes of 73 cichlid fish species from Lake Malawi uncover evolutionary processes underlying a large adaptive evolutionary radiation.

Insights into the evolutionary history of Indo-Pacific bloodfeeding terrestrial leeches (Hirudinida:Arhynchobdellida:Haemadipisdae)

2010 ◽  
Vol 24 (5) ◽  
pp. 456 ◽  
Author(s):  
Elizabeth Borda ◽  
Mark E. Siddall
Keyword(s):  
Pacific Islands ◽  
Sequence Data ◽  
Indian Subcontinent ◽  
Tropical Rainforests ◽  
Mitochondrial Coi ◽  
Biogeographic Patterns ◽  
History Of ◽  
Volcanic Islands ◽  
South Pacific Islands

Haemadipsidae is a clade of notorious bloodfeeding annelids adapted to tropical and sub-tropical rainforests found throughout the Indo-Pacific. This family traditionally includes duognathous (two-jawed) endemics, each placed in their own genus, from continental and volcanic islands including: Australia, Indonesia, Madagascar, Papua New Guinea, Philippines, Seychelles, and South Pacific islands, while trignathous (three-jawed) Tritetrabdella species and the speciose Haemadipsa are exclusive to the Indian subcontinent ranging into east and south-east Asia. One of the more compelling aspects of haemadipsids is their distribution on post-Gondwanan landmasses. In this study, the phylogenetic relationships, taxonomy and biogeographic patterns of Haemadipsidae were examined. Over 5 kb of sequence data from three genes (nuclear 18S rDNA and 28S rDNA and mitochondrial COI) for 37 haemadipsid exemplars, representing 12 of the 15 recognised genera, were analysed under the criteria of maximum parsimony and Bayesian inference. The results show that widespread duognathous species form a monophyletic group derived from trignathous ancestry and are sister to a new trignathous clade for Haemadipsidae. This phylogenetic hypothesis rejected Gondwanan vicariance as an explanation for the diversification of haemadipsids. Haemadipsidae is accepted as the formal name for these Indo-Pacific leeches. Whereas the subdivisions Haemadipsinae and Domanibdellinae are clarified, there is a need to establish a new subfamily, Tritetrabdellinae, for the newly identified trignathous clade that is sister to Domanibdellinae. This study provides a basis for continued elucidation of the evolutionary relationships and classification of these terrestrial annelids.

Galápagos Derailed

2021 ◽  
pp. 83-115
Author(s):  
William H. Durham
Keyword(s):  
Invasive Species ◽  
Pacific Islands ◽  
Human History ◽  
Human Influence ◽  
Flight Ability ◽  
Humid Zone ◽  
Island Populations ◽  
History Of

The same species of Galápagos rail, a 6-inch insectivorous ground bird, has been reported on all eight islands with a highland humid zone. Evidence suggests that the rail colonized Galápagos at roughly the same time as giant tortoises, which evolved into 15 species with life spans of 150 years. So why is there just one species of rail? The question is especially germane given reports of the rail’s “reduced flight ability” (as is true of many island-dwelling rails), which would effectively isolate different island populations. And why has the species survived when so many similar rails have succumbed to human influence on other Pacific islands? The human history of Galápagos helps to answer these questions. Two things have saved the Galápagos rail from extinction: (1) It remains capable of flying between islands, which explains why it failed to differentiate like tortoises. (2) There have been massive efforts to eradicate or control invasive species, restoring habitat for rails to repopulate.

scholarly journals Carybdea alata auct. (Cubozoa): rediscovery of the Alatina grandis type

Zootaxa ◽  
2019 ◽  
Vol 2713 (1) ◽  
pp. 52 ◽  
Author(s):  
BASTIAN BENTLAGE
Keyword(s):  
Evolutionary History ◽  
Phylogenetic Analyses ◽  
Smithsonian Institution ◽  
Type Specimen ◽  
Nominal Species ◽  
Separate Species ◽  
Future Studies ◽  
Molecular Phylogenetic ◽  
History Of ◽  
Morphological Differences

Numerous nominal species have been considered synonymous with Carybdea alata Reynaud, 1830 (cf. Gershwin 2005). A recent revision concluded that several of the species collectively referred to as C. alata are valid and indeed separate species (Gershwin 2005; but see also Bentlage et al. 2010). Additionally, these species (including C. alata) were moved into the genus Alatina Gershwin 2005 (family Alatinidae Gershwin, 2005) because of stark morphological differences they display compared to the other species of Carybdea. In particular, Alatina species possess crescentic phacellae and a rhopaliar niche ostium that is covered by a single upper and two lateral scales (t-shaped sensu Gershwin 2005; cf. Bigelow 1938) compared to a single upper covering scale (heart-shaped sensu Gershwin 2005; cf. Bigelow 1938) and epaulette-like or linear phacellae in the corners of the stomach in Carybdea species. Recent molecular phylogenetic analyses support the separation of Carybdea and Alatina (Bentlage et al. 2010). Alatina grandis posed a problem in Gershwin's (2005) revision, as the type of this species appeared to be lost to science, preventing a closer investigation of its identity. I located a type specimen of the species in the collections of the National Museum of Natural History, Smithsonian Institution (USNM). The purpose of this letter is to draw attention to this important specimen, and highlight directions for future studies on the evolutionary history of the genus Alatina.

Evolution of duplicated growth hormone genes in autotetraploid salmonid fishes

Genome ◽  
2004 ◽  
Vol 47 (4) ◽  
pp. 714-723 ◽  
Author(s):  
S J McKay ◽  
J Trautner ◽  
M J Smith ◽  
B F Koop ◽  
R H Devlin
Keyword(s):  
Growth Hormone ◽  
Evolutionary History ◽  
Sequence Divergence ◽  
Genome Doubling ◽  
Disomic Inheritance ◽  
A Genome ◽  
Gh Gene ◽  
Average Sequence Divergence ◽  
History Of ◽  
Homeologous Chromosomes

A defining character of the piscine family Salmonidae is autotetraploidy resulting from a genome-doubling event some 25–100 million years ago. Initially, duplicated genes may have undergone concerted evolution and tetrasomic inheritance. Homeologous chromosomes eventually diverged and the resulting reduction in recombination and gene conversion between paralogous genes allowed the re-establishment of disomic inheritance. Among extant salmonine fishes (e.g. salmon, trout, char) the growth hormone (GH) gene is generally represented by two functional paralogs, GH1 and GH2. Sequence analyses of salmonid GH genes from species of subfamilies Coregoninae (whitefish, ciscos) and Salmoninae were used to examine the evolutionary history of the duplicated GH genes. Two divergent GH gene paralogs were also identified in Coregoninae, but they were not assignable to the GH1 and GH2 categories. The average sequence divergence between the coregonine GH genes was more than twofold lower than the corresponding divergence between the salmonine GH1 and GH2. Phylogenetic analysis of the coregonine GH paralogs did not resolve their relationship to the salmonine paralogs. These findings suggest that disomic inheritance of two GH genes was established by different mechanisms in these two subfamilies.Key words: salmon, phylogeny, growth hormone, disomy, tetraploidy.

scholarly journals The English strain of rat cytomegalovirus (CMV) contains a novel captured CD200 (vOX2) gene and a spliced CC chemokine upstream from the major immediate-early region: further evidence for a separate evolutionary lineage from that of rat CMV Maastricht

2005 ◽  
Vol 86 (2) ◽  
pp. 263-274 ◽  
Author(s):  
Sebastian Voigt ◽  
Gordon R. Sandford ◽  
Gary S. Hayward ◽  
William H. Burns
Keyword(s):  
Time Course ◽  
Sequence Data ◽  
Phylogenetic Analyses ◽  
Receptor Gene ◽  
Sequence Divergence ◽  
Northern Blotting ◽  
Immediate Early ◽  
Murine Cytomegalovirus ◽  
Separate Species ◽  
The Right

Sequence data for eight genes, together with time-course Northern blotting and 3′- and 5′-RACE (rapid amplification of cDNA ends) analysis for some mRNAs from a 12 kb region upstream from the major immediate-early (MIE) genes of the English isolate of rat cytomegalovirus (RCMV), are presented. The results identified important differences compared to both murine cytomegalovirus (MCMV) and the Maastricht isolate of RCMV. A striking finding is the presence of a highly conserved, rightwards-oriented homologue of the rat cellular CD200 (OX2) gene immediately to the right of the MIE region, which replaces either the leftwards-oriented AAV REP gene of RCMV (Maastricht) or the upstream spliced portions of the immediate-early 2 gene (ie2) in MCMV. From the presence of other homologues of MCMV- and RCMV-specific genes, such as the β-chemokine MCK-2, SGG1 and an Fcγ receptor gene, as reported here, the basic architecture of the MIE region (reported previously) and the level of IE2 and DNA polymerase (POL) protein conservation in phylogenetic analyses, it is clear that the English strain of RCMV is also a member of the genus Muromegalovirus, but is a β-herpesvirus species that is very distinct from both MCMV and RCMV (Maastricht). Both the lack of a CD200 homologue in the other two rodent viruses and the depth of sequence divergence of the rodent CMV IE2 and POL proteins suggest that these three viruses have evolved as separate species in the genus Muromegalovirus since very early in the host rodent lineage.

scholarly journals A Population Genetics-Based and Phylogenetic Approach to Understanding the Evolution of Virulence in the Genus Listeria

2010 ◽  
Vol 76 (18) ◽  
pp. 6085-6100 ◽  
Author(s):  
Henk C. den Bakker ◽  
Brittany N. Bundrant ◽  
Esther D. Fortes ◽  
Renato H. Orsi ◽  
Martin Wiedmann
Keyword(s):  
Gene Cluster ◽  
Phylogenetic Analyses ◽  
Sequence Divergence ◽  
Virulence Gene ◽  
Selective Advantage ◽  
Opportunistic Pathogens ◽  
Evolution Of Virulence ◽  
Average Sequence Divergence ◽  
Phylogeny And Evolution ◽  
Environmental Pathogens

ABSTRACT The genus Listeria includes (i) the opportunistic pathogens L. monocytogenes and L. ivanovii, (ii) the saprotrophs L. innocua, L. marthii, and L. welshimeri, and (iii) L. seeligeri, an apparent saprotroph that nevertheless typically contains the prfA virulence gene cluster. A novel 10-loci multilocus sequence typing scheme was developed and used to characterize 67 isolates representing six Listeria spp. (excluding L. grayi) in order to (i) provide an improved understanding of the phylogeny and evolution of the genus Listeria and (ii) use Listeria as a model to study the evolution of pathogenicity in opportunistic environmental pathogens. Phylogenetic analyses identified six well-supported Listeria species that group into two main subdivisions, with each subdivision containing strains with and without the prfA virulence gene cluster. Stochastic character mapping and phylogenetic analysis of hly, a gene in the prfA cluster, suggest that the common ancestor of the genus Listeria contained the prfA virulence gene cluster and that this cluster was lost at least five times during the evolution of Listeria, yielding multiple distinct saprotrophic clades. L. welshimeri, which appears to represent the most ancient clade that arose from an ancestor with a prfA cluster deletion, shows a considerably lower average sequence divergence than other Listeria species, suggesting a population bottleneck and a putatively different ecology than other saprotrophic Listeria species. Overall, our data suggest that, for some pathogens, loss of virulence genes may represent a selective advantage, possibly by facilitating adaptation to a specific ecological niche.

Evidence of cryptic speciation in mesostigmatid mites from South Africa

Parasitology ◽  
2014 ◽  
Vol 141 (10) ◽  
pp. 1322-1332 ◽  
Author(s):  
ADRIAAN ENGELBRECHT ◽  
CONRAD A. MATTHEE ◽  
EDWARD A. UECKERMANN ◽  
SONJA MATTHEE
Keyword(s):  
South Africa ◽  
Nuclear Dna ◽  
Phylogenetic Analyses ◽  
Strong Support ◽  
Sequence Divergence ◽  
Morphological Diversity ◽  
Morphometric Analyses ◽  
Mtdna Sequence ◽  
History Of ◽  
Complex Life History

SUMMARYLaelaps giganteus and Laelaps muricola (Mesostigmata; Laelapidae) are widespread and locally abundant host generalists on small mammals in southern Africa. The large host range and complex life history of these ectoparasites may allude to possible intraspecific cryptic diversity in these taxa. To assess genetic and morphological diversity in L. giganteus and L. muricola, we sampled 228 rodents at eight localities in South Africa. This sample included nine previously recorded host species and on these, L. muricola was only recorded from Mastomys natalensis and Micaelamys namaquensis while L. giganteus was found on Rhabdomys dilectus and Lemniscomys rosalia. Phylogenetic analyses of partial mtDNA cytochrome oxidase subunit I (COI) and nuclear ITS1 data strongly supported the recognition of L. giganteus and L. muricola, a scenario partly supported by the Tropomyosin intron. Strong support for evolutionary distinct lineages within L. giganteus is found: L. giganteus lineage 1 is confined to R. dilectus and L. giganteus lineage 2 is confined to L. rosalia. These host specific monophyletic lineages were also separated by 9·84% mtDNA sequence divergence and 3·44% nuclear DNA sequence divergence. Since quantitative morphometric analyses were not congruent with these findings, these two lineages more than likely represent cryptic species.

The dilemma of the South Pacific islands : states, tradition, ethnicity.

1991 ◽  
Vol 92 (1) ◽  
pp. 163-172 ◽  
Author(s):  
Sachiko Hatanaka
Keyword(s):  
Pacific Islands ◽  
South Pacific ◽  
The South ◽  
South Pacific Islands
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