scholarly journals From Settlers to Subspecies: Genetic Differentiation in Commerson’s Dolphins Between South America and the Kerguelen Islands

2021 ◽  
Vol 8 ◽  
Author(s):  
Sebastián Kraft ◽  
MJosé Pérez-Alvarez ◽  
Carlos Olavarría ◽  
Rodrigo Moraga ◽  
C. Scott Baker ◽  
...  
Keyword(s):  
South America ◽  
Distinct Group ◽  
Threshold Value ◽  
Haplotype Network ◽  
Diversity Indices ◽  
Phylogeographic Structure ◽  
Source Population ◽  
Long Distance ◽  
Tissue Samples ◽  
Kerguelen Islands

Commerson’s dolphins (Cephalorhynchus commersonii) are separated into the subspecies C. c. commersonii, found along southern South America (SA) and the Falkland Islands/Islas Malvinas (FI/IM), and C. c. kerguelenensis, restricted to the subantarctic Kerguelen Islands (KI). Following the dispersal model proposed for the genus, the latter is thought to have originated from SA after a long-distance dispersal event. To evaluate this biogeographic scenario, a distribution-wide, balanced sampling of mitochondrial DNA (mtDNA) control region sequences was designed. New tissue samples from southern Chile, Argentina, FI/IM, and KI were added to published sequences from SA and KI, for a total of 256 samples. Genetic diversity indices, genetic and phylogeographic structure, and migration rates were calculated. One haplotype was shared between subspecies, with which all haplotypes of C. c. kerguelenensis formed a distinct group in the haplotype network. A new haplotype for C. c. kerguelenensis is reported. Differentiation in haplotype frequencies was found among localities within the distribution of C. c. commersonii, yet the phylogeographic signal was only statistically significant between subspecies. Coalescent-based historical gene flow estimations indicated migration between the northern and southern portions of the species’ range in SA as well as between SA and the FI/IM, but not between these and the KI. The net nucleotide divergence between dolphins from SA and the FI/IM was lower than the recommended threshold value suggested for delimiting subspecies, unlike that found between C. c. commersonii and C. c. kerguelenensis. The results are consistent with the model of post-glacial colonization of KI by South American C. commersonii, followed by an ongoing divergence process and subspecies status. Thus, C. c. kerguelenensis may represent the most recent diversification step of Cephalorhynchus, where isolation from their source population is driving a process of incipient speciation.

scholarly journals Genetic melting pot and importance of long-distance dispersal indicated in the Gladiolus imbricatus L. populations in the Polish Carpathians

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Agnieszka Sutkowska ◽  
Józef Mitka ◽  
Tomasz Warzecha ◽  
Jakub Bunk ◽  
Julia Rutkowska ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Diversity Indices ◽  
Western Carpathians ◽  
Genetic Structuring ◽  
Long Distance ◽  
Plant Populations ◽  
Genetic Stock ◽  
Melting Pot ◽  
Mountain Ranges ◽  
Eastern Carpathians

AbstractThe genetic diversity in 11 populations of Gladiolus imbricatus in five mountain ranges, including the Tatra, Pieniny, Gorce, Beskid Niski (Western Carpathians) and Bieszczady Mts (Eastern Carpathians), was studied with inter-simple sequence repeat (ISSR) markers. The species is a perennial plant occurring in open and semi-open sites of anthropogenic origin (meadows and forest margins). We checked a hypothesis on the microrefugial character of the plant populations in the Pieniny Mts, a small calcareous Carpathian range of complicated relief that has never been glaciated. Plant populations in the Tatra and Pieniny Mts had the highest genetic diversity indices, pointing to their long-term persistence. The refugial vs. the non-refugial mountain ranges accounted for a relatively high value of total genetic variation [analysis of molecular variance (AMOVA), 14.12%, p = 0.003]. One of the Pieniny populations was of hybridogenous origin and shared genetic stock with the Tatra population, indicating there is a local genetic melting pot. A weak genetic structuring of populations among particular regions was found (AMOVA, 4.5%, p > 0.05). This could be an effect of the frequent short-distance and sporadic long-distance gene flow. The dispersal of diaspores between the remote populations in the Western Carpathians and Eastern Carpathians could be affected by the historical transportation of flocks of sheep from the Tatra to Bieszczady Mts.

scholarly journals Memoirs of a frequent flier: Phylogenomics reveals 18 long-distance dispersals between North America and South America in the popcorn flowers (Amsinckiinae)

2017 ◽  
Vol 104 (11) ◽  
pp. 1717-1728 ◽  
Author(s):  
C. Matt Guilliams ◽  
Kristen E. Hasenstab-Lehman ◽  
Makenzie E. Mabry ◽  
Michael G. Simpson
Keyword(s):  
North America ◽  
South America ◽  
Long Distance

Driftwood on Heard Island

Polar Record ◽  
1989 ◽  
Vol 25 (154) ◽  
pp. 223-228 ◽  
Author(s):  
J. M. B. Smith ◽  
P. Rudall ◽  
P. L. Keage
Keyword(s):  
South America ◽  
South American ◽  
Long Distance Dispersal ◽  
South American Species ◽  
Long Distance ◽  
Heard Island

AbstractSamples from 73 pieces of non-structural driftwood on Heard Island (53°06′S, 73°30′E) were identified to genus or species. Thirty-one belonged to South American species of Nothofagus. The remainder, consisting mostly of conifers especially Picea and Larix, probably came from ships' cargoes. The assemblage is similar to those reported, from smaller samples, on other southern islands. Other items of flotsam, including fishing buoys and drift-cards, are also reported from Heard Island. The significance of driftwood transport from South America to the island in accounting for long-distance dispersal of terrestrial and intertidal organisms is discussed.

scholarly journals A description and summary of the Antarctic Humpback Whale Catalogue

2020 ◽  
pp. 95-99
Author(s):  
Judith Allen ◽  
Carole Carlson ◽  
Peter T. Stevick
Keyword(s):  
South America ◽  
Southern Ocean ◽  
Antarctic Peninsula ◽  
Humpback Whale ◽  
Humpback Whales ◽  
Western Coast ◽  
Long Distance ◽  
Dorsal Fin ◽  
Feeding Area ◽  
The Antarctic

The Antarctic Humpback Whale Catalogue (AHWC) is an international collaborative project investigating movement patterns of humpback whales in the Southern Ocean and corresponding lower latitude waters. The collection contains records contributed by 261 researchers and opportunistic sources. Photographs come from all of the Antarctic management areas, the feeding grounds in southern Chile and also most of the known or suspected low-latitude breeding areas and span more than two decades. This allows comparisons to be made over all of the major regions used by  Southern Hemisphere humpback whales. The fluke, left dorsal fin/flank and right dorsal fin/flank collections represent 3,655, 413 and 407 individual whales respectively. There were 194 individuals resighted in more than one year, and 82 individuals resighted in more than one region. Resightings document movement along the western coast of South America and movement between the Antarctic Peninsula and western coast of South America and Central America. A single individual from Brazil was resighted off South Georgia, representing the first documented link between the Brazilian breeding ground and any feeding area. A second individual from Brazil was resighted off Madagascar, documenting long distance movement of a female between non-adjacent breeding areas. Resightings also include two matches between American Samoa and the Antarctic Peninsula, documenting the first known feeding site for American Somoa and setting a new long distance seasonal migration record. Three matches between Sector V and eastern Australia support earlier evidence provided by Discovery tags. Multiple resightings of individuals in the Antarctic Peninsula during more than one season indicate that humpback whales in this area show some degree of regional feeding area fidelity. The AHWC provides a powerful non-lethal and non-invasive tool for investigating the movements and population structure of the whales utilising the Southern Ocean Sanctuary. Through this methodical, coordinated comparison and maintenance of collections from across the hemisphere, large-scale movement patterns may be examined, both within the Antarctic, and from the Antarctic to breeding grounds at low latitudes.

scholarly journals Evolution of andrenine bees reveals a long and complex history of faunal interchanges between the Americas during the Mesozoic and Cenozoic

2021 ◽  
Author(s):  
Kelli S Ramos ◽  
Aline C Martins ◽  
Gabriel A R Melo
Keyword(s):  
North America ◽  
South America ◽  
Time Window ◽  
Distributional Pattern ◽  
Long Distance ◽  
Early Diversification ◽  
Palearctic Region ◽  
Long Time ◽  
The Times ◽  
Dated Phylogeny

Bees are presumed to have arisen in the early to mid-Cretaceous coincident with the fragmentation of the southern continents and concurrently with the early diversification of the flowering plants. Among the main groups of bees, Andreninae sensu lato comprise about 3000 species widely distributed with greatest and disjunct diversity in arid areas of North America, South America, and the Palearctic region. Here, we present the first comprehensive dated phylogeny and historical biogeographic analysis for andrenine bees, including representatives of all currently recognized tribes. Our analyses rely on a dataset of 106 taxa and 7952 aligned nucleotide positions from one mitochondrial and six nuclear loci. Andreninae is strongly supported as a monophyletic group and the recovered phylogeny corroborates the commonly recognized clades for the group. Thus, we propose a revised tribal classification that is congruent with our phylogenetic results. The time-calibrated phylogeny and ancestral range reconstructions of Andreninae reveal a fascinating evolutionary history with Gondwana patterns that are unlike those observed in other subfamilies of bees. Andreninae arose in South America during the Late Cretaceous around 90 Million years ago (Ma) and the origin of tribes occurred through a relatively long time-window from this age to the Miocene. The early evolution of the main lineages took place in South America until the beginning of Paleocene with North American fauna origin from it and Palearctic from North America as results of multiple lineage interchanges between these areas by long-distance dispersal or hopping through landmass chains. Overall, our analyses provide strong evidence of amphitropical distributional pattern currently observed in Andreninae in the American continent as result at least three periods of possible land connections between the two American landmasses, much prior to the Panama Isthmus closure. The andrenine lineages reached the Palearctic region through four dispersal events from North America during the Eocene, late Oligocene and early Miocene, most probably via the Thulean Bridge. The few lineages with Afrotropical distribution likely originated from a Palearctic ancestral in the Miocene around 10 Ma when these regions were contiguous, and the Sahara Desert was mostly vegetated making feasible the passage by several organisms. Incursions of andrenine bees to North America and then onto the Old World are chronological congruent with distinct periods when open-vegetation habitats were available for trans-continental dispersal and at the times when aridification and temperature decline offered favorable circumstances for bee diversification.

First fossil crabs (Crustacea, Decapoda, Brachyura) from the Kerguelen Islands (Miocene) with exceptionally preserved gills

2018 ◽  
Vol 92 (3) ◽  
pp. 466-477
Author(s):  
Ninon Robin ◽  
Barry W.M. Van Bakel ◽  
Marie-Madeleine Blanc-Valleron ◽  
Pierre Y. Noël ◽  
Laurent Lemaire ◽  
...  
Keyword(s):  
South America ◽  
Soft Tissues ◽  
Specific Interest ◽  
Migration Routes ◽  
Morphological Comparison ◽  
X Ray ◽  
Kerguelen Islands ◽  
Fossil Material ◽  
Geochemical Analyses ◽  
Cheilostome Bryozoans

AbstractKerguelen Islands are predominantly volcanic lands, thus fossil references are very uncommon. However, its Miocene fossils are of specific interest for understanding migration routes of some taxa during the Cenozoic, given the intermediary position of Kerguelen with various continents. Despite this fossil rarity, we studied herein hundreds of nodules corresponding to the sole known fossil brachyurans (and unique Decapoda) from Kerguelen both for their systematics and their preservation. Indeed, these crabs display some internal fragile structures that are rarely fossilized, such as the gills’ branchial lamellae, preserved in volume. The preservation of these gills and their diagenetic features were documented through traditional imagery (SEM), including morphological comparison to modern gills, and with petrographic and geochemical analyses (EDS, X-ray diffractometry). Some cheilostome bryozoans were observed as probable foulers of the crabs carcasses. The fossil material corresponds to a new cancrid crab (Romaleon franciscaen. sp.) and its occurrence may imply a novel route from South America westward for the geographic migration of the genusRomaleon, since its Cretaceous emergence. The cup-shape and the number and the organization of the gills in these fossil Cancridae specimens are similar to those observed in their extant representatives. Gill preservation in 3D is linked to very early phosphatization of the system during diagenesis, as shown by the nodule matrix, and likely to deposition of a thin clayey cover on the soft-tissues. The implication of intrinsic phosphorous in the differential phosphatization of the crabs’ anatomy remains difficult to determine.

scholarly journals Genetic Structure and Phylogenetic Relationships of Capsicum chinense

2012 ◽  
Vol 137 (4) ◽  
pp. 250-262 ◽  
Author(s):  
Marissa Moses ◽  
Pathmanathan Umaharan
Keyword(s):  
South America ◽  
Diversity Indices ◽  
Amazon Region ◽  
Greater Antilles ◽  
Capsicum Chinense ◽  
Arbitrary Primers ◽  
Geographical Regions ◽  
Major Cluster ◽  
Phylogenetic Origin ◽  
The Caribbean

Capsicum chinense is commercially the most important pepper species grown in the Caribbean. It is popularly used to impart pungency and flavor to Caribbean cuisine. However, unlike Capsicum annuum, which is the most commercially exploited domesticated species internationally, C. chinense has not been methodically collected or characterized for systematic improvement through plant breeding. The objectives of the study were to assess the diversity of C. chinense and its structure within the Caribbean basin and to determine its phylogenetic relationship to groups within South America. DNA isolated from 201 accessions of C. chinense, representing geographical regions where the species is found, were amplified using arbitrary primers to generate 138 polymorphic and reproducible random amplification of polymorphic DNA (RAPD) markers. Nei’s and Shannon’s diversity indices for C. chinense (0.28 and 0.419, respectively) were higher in South America compared with Central America or the Caribbean, corresponding to its putative center of diversity. The study showed the existence of three phylogenetic clusters within C. chinense. The largest cluster consisted of accessions from the Upper Amazon region, the Guianas including Venezuela, and the Lesser Antilles of the Caribbean. The other major cluster was represented by accessions principally from the Lower Amazon region. Another distinct but small cluster consisted of samples solely from the Greater Antilles of the Caribbean. The discovery of the three phylogenetic clusters within C. chinense may have potential for exploiting heterosis in breeding. The implications of the findings to the understanding of the phylogenetic origin and distribution of C. chinense are discussed.

Muscle fiber types and size in trained and untrained muscles of elite athletes

1985 ◽  
Vol 59 (6) ◽  
pp. 1716-1720 ◽  
Author(s):  
P. A. Tesch ◽  
J. Karlsson
Keyword(s):  
Muscle Fiber ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Deltoid Muscle ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Relative Distribution ◽  
Long Distance ◽  
Tissue Samples ◽  
Greco Roman

Tissue samples were obtained from vastus lateralis and deltoid muscles of physical education students (n = 12), Greco-Roman wrestlers (n = 8), flat-water kayakers (n = 9), middle- and long-distance runners (n = 9), and olympic weight and power lifters (n = 7). Histochemical stainings for myofibrillar adenosinetriphosphatase and NADH-tetrazolium reductase were applied to assess the relative distribution of fast-twitch and slow-twitch (ST) muscle fiber types and fiber size. The %ST was not different in the vastus (mean SD 48 +/- 14) and deltoid (56 +/- 13) muscles. The %ST was higher (P less than 0.001), however, in the deltoid compared with vastus muscle of kayakers. This pattern was reversed in runners (P less than 0.001). The %ST of the vastus was higher (P less than 0.001) in runners than in any of the other groups. The %ST of the deltoid muscle was higher in kayakers than in students, runners (P less than 0.001), and lifters (P less than 0.05). The mean fiber area and the area of ST fibers were greater (P less than 0.01) in the vastus than the deltoid muscle. Our data show a difference in fiber type distribution between the trained and nontrained muscles of endurance athletes. This pattern may reflect the adaptive response to long-term endurance training.

Mitochondrial DNA variation of the west-coast rock lobster, Jasus lalandii: marked genetic diversity differences among sampling sites

2007 ◽  
Vol 58 (12) ◽  
pp. 1130 ◽  
Author(s):  
Conrad A. Matthee ◽  
Andrew C. Cockcroft ◽  
Keshni Gopal ◽  
Sophie von der Heyden
Keyword(s):  
Genetic Diversity ◽  
West Coast ◽  
Haplotype Network ◽  
Phylogeographic Structure ◽  
Rrna Gene ◽  
Rock Lobster ◽  
The West ◽  
Mt Dna ◽  
Dna Variation ◽  
Intensive Exploitation

Jasus lalandii (Milne-Edwards 1837), the west-coast rock lobster, occurs in the shallow, cool–temperate waters along the south and west coasts of southern Africa. This species has a long history of intensive exploitation, which has had a significant impact on population numbers in the past. To enhance our current understanding of lobster population structuring, genetic data from the mitochondrial (mt) DNA 16S rRNA gene was generated for 235 adult individuals collected at eight sampling sites. Most individuals (59.6%) share a common haplotype and 35 unique haplotypes were dispersed throughout the range. In total, 97.2% of the variation was found among individuals within sampling sites and 2.8% was among sites. Pairwise ΦST analyses revealed shallow, yet significant structure between Hout Bay individuals and some other sampling sites. The J. lalandii haplotype network indicates a starlike structure with no geographic signal; however, genetic diversity sharply decreases towards the edges of the species distribution. The general lack of phylogeographic structure among J. lalandii populations probably results from the absence of strong barriers to larval dispersal. Based on our mtDNA data there is no justification for the recognition of separate fishing stocks, but the high genetic diversities of populations at Hout Bay and Cape Hangklip, the latter currently outside of marine protected areas, makes these populations critical to conservation efforts.

Sign in / Sign up

Export Citation Format

Share Document