scholarly journals A rapid loss of stripes: the evolutionary history of the extinct quagga

2005 ◽  
Vol 1 (3) ◽  
pp. 291-295 ◽  
Author(s):  
Jennifer A Leonard ◽  
Nadin Rohland ◽  
Scott Glaberman ◽  
Robert C Fleischer ◽  
Adalgisa Caccone ◽  
...  

Twenty years ago, the field of ancient DNA was launched with the publication of two short mitochondrial (mt) DNA sequences from a single quagga ( Equus quagga ) museum skin, an extinct South African equid ( Higuchi et al . 1984 Nature 312 , 282–284). This was the first extinct species from which genetic information was retrieved. The DNA sequences of the quagga showed that it was more closely related to zebras than to horses. However, quagga evolutionary history is far from clear. We have isolated DNA from eight quaggas and a plains zebra (subspecies or phenotype Equus burchelli burchelli ). We show that the quagga displayed little genetic diversity and very recently diverged from the plains zebra, probably during the penultimate glacial maximum. This emphasizes the importance of Pleistocene climate changes for phylogeographic patterns in African as well as Holarctic fauna.

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Masahiko Muraji ◽  
Norio Arakaki ◽  
Shigeo Tanizaki

The phylogenetic relationship, biogeography, and evolutionary history of closely related two firefly species,Curtos costipennisandC. okinawanus, distributed in the Ryukyu Islands of Japan were examined based on nucleotide sequences of mitochondrial (2.2 kb long) and nuclear (1.1-1.2 kb long) DNAs. In these analyses, individuals were divided among three genetically distinct local groups,C. costipennisin the Amami region,C. okinawanusin the Okinawa region, andC. costipennisin the Sakishima region. Their mtDNA sequences suggested that ancestralC. costipennispopulation was first separated between the Central and Southern Ryukyu areas, and the northern half was then subdivided betweenC. costipennisin the Amami andC. okinawanusin the Okinawa. The application of the molecular evolutionary clocks of coleopteran insects indicated that their vicariance occurred 1.0–1.4 million years ago, suggesting the influence of submergence and subdivision of a paleopeninsula extending between the Ryukyu Islands and continental China through Taiwan in the early Pleistocene.


1993 ◽  
Vol 67 (4) ◽  
pp. 549-570 ◽  
Author(s):  
Bruce S. Lieberman

Phylogenetic parsimony analysis was used to classify the Siegenian–Eifelian “Metacryphaeus group” of the family Calmoniidae. Thirty-eight exoskeletal characters for 16 taxa produced a shortest-length cladogram with a consistency index of 0.49. A classification based on retrieving the structure of this cladogram recognizes nine genera: Typhloniscus Salter, Plesioconvexa n. gen., Punillaspis Baldis and Longobucco, Eldredgeia n. gen., Clarkeaspis n. gen., Malvinocooperella n. gen., Wolfartaspis Cooper, Plesiomalvinella Lieberman, Edgecombe, and Eldredge (used to represent the malvinellid clade), and Metacryphaeus Reed. The malvinellid clade is most closely related to a revised monophyletic Metacryphaeus. Typhloniscus is the basal member of the “Metacryphaeus group,” and the monotypic Wolfartaspis is sister to the clade containing the malvinellids and Metacryphaeus. Six new species are diagnosed: Punillaspis n. sp. A, “Clarkeaspis” gouldi, Clarkeaspis padillaensis, Malvinocooperella pregiganteus, Metacryphaeus curvigena, and Metacryphaeus branisai. Primitively, this group has South African and Andean affinities, and its evolutionary history suggests rapid diversification. In addition, evolutionary patterns in this group, and the distribution of character reversals, call into question certain notions about the nature of adaptive radiations. The distributions of taxa may answer questions about the number of marine transgressive/regressive cycles in the Emsian–Eifelian of the Malvinokaffric Realm.


2019 ◽  
Vol 158 (2) ◽  
pp. 98-105 ◽  
Author(s):  
Suziane A. Barcellos ◽  
Rafael Kretschmer ◽  
Marcelo S. de Souza ◽  
Alice L. Costa ◽  
Tiago M. Degrandi ◽  
...  

As in many other bird groups, data on karyotype organization and distribution of repetitive sequences are also lacking in species belonging to the family Hirundinidae. Thus, in the present study, we analyzed the karyotypes of 3 swallow species (Progne tapera, Progne chalybea, and Pygochelidon cyanoleuca) by Giemsa and AgNOR staining, C-banding, and FISH with 11 microsatellite sequences. The diploid chromosome number was 2n = 76 in all 3 species, and NORs were observed in 2 chromosome pairs each. The microsatellite distribution pattern was similar in both Progne species, whereas P. cyanoleuca presented a distinct organization. These repetitive DNA sequences were found in the centromeric, pericentromeric, and telomeric regions of the macrochromosomes, as well as in 2 interstitial blocks in the W chromosome. Most microchromosomes had mainly telomeric signals. The Z chromosome displayed 1 hybridization signal in P. tapera but none in the other species. In contrast, the W chromosome showed an accumulation of different microsatellite sequences. The swallow W chromosome is larger than that of most Passeriformes. The observed enlargement in chromosome size might be explained by these high amounts of repetitive sequences. In sum, our data highlight the significant role that microsatellite sequences may play in sex chromosome differentiation.


2006 ◽  
Vol 189 (4) ◽  
pp. 1238-1243 ◽  
Author(s):  
Page W. Caufield ◽  
Deepak Saxena ◽  
David Fitch ◽  
Yihong Li

ABSTRACT There are suggestions that the phylogeny of Streptococcus mutans, a member of the human indigenous biota that is transmitted mostly mother to child, might parallel the evolutionary history of its human host. The relatedness and phylogeny of plasmid-containing strains of S. mutans were examined based on chromosomal DNA fingerprints (CDF), a hypervariable region (HVR) of a 5.6-kb plasmid, the rRNA gene intergenic spacer region (IGSR), serotypes, and the genotypes of mutacin I and II. Plasmid-containing strains were studied because their genetic diversity was twice as great as that of plasmid-free strains. The CDF of S. mutans from unrelated human hosts were unique, except those from Caucasians, which were essentially identical. The evolutionary history of the IGSR, with or without the serotype and mutacin characters, clearly delineated an Asian clade. Also, a continuous association with mutacin II could be reconstructed through an evolutionary lineage with the IGSR, but not for serotype e. DNA sequences from the HVR of the plasmid produced a well-resolved phylogeny that differed from the chromosomal phylogeny, indicating that the horizontal transfer of the plasmid may have occurred multiple times. The plasmid phylogeny was more congruent with serotype e than with mutacin II evolution, suggesting a possible functional correlation. Thus, the history of this three-tiered relationship between human, bacterium, and plasmid supported both coevolution and independent evolution.


2019 ◽  
Vol 125 (1) ◽  
pp. 105-117 ◽  
Author(s):  
Yixuan Kou ◽  
Li Zhang ◽  
Dengmei Fan ◽  
Shanmei Cheng ◽  
Dezhu Li ◽  
...  

Abstract Background and Aims Many monotypic gymnosperm lineages in south-east China paradoxically remain in relict status despite long evolutionary histories and ample opportunities for allopatric speciation, but this paradox has received little attention and has yet to be resolved. Here, we address this issue by investigating the evolutionary history of a relict conifer, Pseudotaxus chienii (Taxaceae). Methods DNA sequences from two chloroplast regions and 14 nuclear loci were obtained for 134 samples. The demographic history was inferred and the contribution of isolation by environment (IBE) in patterning genetic divergence was compared with that of isolation by distance (IBD). Key Results Three genetic clusters were identified. Approximate Bayesian computation analyses showed that the three clusters diverged in the late Pliocene (~3.68 Ma) and two admixture events were detected. Asymmetric gene flow and similar population divergence times (~ 3.74 Ma) were characterized using the isolation with migration model. Neither IBD nor IBE contributed significantly to genetic divergence, and the contribution of IBE was much smaller than that of IBD. Conclusions These results suggest that several monotypic relict gymnosperm lineages like P. chienii in south-east China did not remain in situ and undiversified for millions of years. On the contrary, they have been evolving and the extant populations have become established more recently, having insufficient time to speciate. Our findings provide a new perspective for understanding the formation and evolution of the relict gymnosperm flora of China as well as of the Sino-Japanese Flora.


2020 ◽  
Vol 195 (1) ◽  
pp. 77-92
Author(s):  
Geraldo Mäder ◽  
Priscilla M Zamberlan ◽  
Ana Lucia A Segatto ◽  
João R Stehmann ◽  
Sandro L Bonatto ◽  
...  

Abstract The Brazilian Atlantic Forest (BAF) is one of the most impacted biomes in the world, and in this region, there are several examples of the effects of Pleistocene climate changes among the species found there. Athenaea fasciculata (Solanaceae) is a forest component distributed mainly throughout the BAF extension. Here, we investigated the genetic diversity and population structure of A. fasciculata based on plastid and nuclear markers, aiming to better understand the impact of Pleistocene climate changes on BAF vegetation. We used population genetics, demographic methods and ecological niche modelling coupled to an evolutionary approach to describe the species distribution across time. The phylogeographic analysis of A. fasciculata indicated that Pleistocene climate changes played an important role in its evolution. The species is structured in two groups of populations that emerged from different refugia and were under different climate influences, supporting previously proposed connections between the Atlantic and Amazon Forests, the two most important Neotropical rainforests.


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