Ancient DNA from a 2,500-year-old Caribbean fossil places an extinct bird (Caracara creightoni) in a phylogenetic context

Extinction in the Anthropocene.

The aim of this work was to investigate a very common situation in the archaeological and anthropological context: the study of a burial site containing several individuals, probably related genetically, using ancient DNA techniques. We used available ancient DNA and forensic protocols to obtain reliable results on archaeological material. The results also enabled molecular sex determination to be compared with osteological data. Specifically, a modified ancient DNA extraction method combined with the amplification of nuclear markers with the AmpFlSTR®MiniFiler™ kit(Applied Biosystems) was used. Seven medieval individuals buried in four niches dated in the 15th Century at San Esteban Church in Cuellar (Segovia, Central Spain) were analyzed by the proposed method, and four of seven provided complete autosomal short tandem repeat (STRs) profiles. Kinship analyses comprising paternity and sibship relations were carried out with pedigree-specific software used in forensic casework. A 99.98% paternity probability was established between two individuals, although lower percentages (68%) were obtained in other cases, and some hypothetical kinship relations were excluded. The overall results could eventually provide evidence for reconstructing the historical record.

Comparative and population mitogenomic analyses of Madagascar's extinct, giant ‘subfossil’ lemurs

Co-evolution has an important function in the evolution of species and it is clearly manifested in certain scenarios such as host–parasite and predator–prey interactions, symbiosis and mutualism. The extrapolation of the concepts and methodologies developed for the study of species co-evolution at the molecular level has prompted the development of a variety of computational methods able to predict protein interactions through the characteristics of co-evolution. Particularly successful have been those methods that predict interactions at the genomic level based on the detection of pairs of protein families with similar evolutionary histories (similarity of phylogenetic trees: mirrortree). Future advances in this field will require a better understanding of the molecular basis of the co-evolution of protein families. Thus, it will be important to decipher the molecular mechanisms underlying the similarity observed in phylogenetic trees of interacting proteins, distinguishing direct specific molecular interactions from other general functional constraints. In particular, it will be important to separate the effects of physical interactions within protein complexes (‘co-adaptation') from other forces that, in a less specific way, can also create general patterns of co-evolution.

Fossil DNA.

Specimen-based taxonomic research is essential for understanding diversity and setting management frameworks for threatened mammal faunas, and ancient DNA techniques are increasingly used to extract information from taxonomically relevant historical specimens. The largest survivors of the depleted Caribbean mammal fauna are hutias in the genus Capromys, which is usually interpreted as containing a single species, C. pilorides. Previous studies have demonstrated genetic differentiation of Capromys populations across Cuba, but infrageneric species diversity and nomenclature remain unclear. We conducted ancient DNA analysis of historical Capromys samples using cytochrome b and complete mitogenome data sets, and including the 19th-century holotypes of 2 species now considered synonyms, C. fournieri and C. geayi. Our analyses identify distinct western and central/eastern Capromys clades that diverged 1.75 Mya based upon mitogenome data. These clades are separated by the Havana–Matanzas Channel, which represented a barrier to dispersal throughout the Neogene–Quaternary. Divergence date comparisons with other hutia species provide support for interpreting divergence between Capromys populations as species-level differentiation. Although we were unable to yield amplifiable DNA from the C. fournieri holotype, our analyses confidently assign the C. geayi holotype to the western Capromys clade. We therefore recognize 2 extant Capromys species: C. geayi (western Cuba) and C. pilorides (central/eastern Cuba and Cayman Islands).

Natural history museum collections represent a vast source of ancient and historical DNA samples from extinct taxa that can be utilized by high-throughput sequencing tools to reveal novel genetic and phylogenetic information about them. Here, we report on the successful sequencing of complete mitochondrial genome sequences (mitogenomes) from eleven extinct bird species, using de novo assembly of short sequences derived from toepad samples of degraded DNA from museum specimens. For two species (the Passenger Pigeon Ectopistes migratorius and the South Island Piopio Turnagra capensis), whole mitogenomes were already available from recent studies, whereas for five others (the Great Auk Pinguinis impennis, the Imperial Woodpecker Campehilus imperialis, the Huia Heteralocha acutirostris, the Kauai Oo Moho braccathus and the South Island Kokako Callaeas cinereus), there were partial mitochondrial sequences available for comparison. For all seven species, we found sequence similarities of >98%. For the remaining four species (the Kamao Myadestes myadestinus, the Paradise Parrot Psephotellus pulcherrimus, the Ou Psittirostra psittacea and the Lesser Akialoa Akialoa obscura), there was no sequence information available for comparison, so we conducted blast searches and phylogenetic analyses to determine their phylogenetic positions and identify their closest extant relatives. These mitogenomes will be valuable for future analyses of avian phylogenetics and illustrate the importance of museum collections as repositories for genomics resources.

Understanding evolutionary transitions in scleractinian corals is fundamental to predicting responses of coral reefs to climate change. We examine transitions between solitary and colonial corals in the fossil record, focusing on the Caribbean solitary reef coral Scolymia and members of the subfamily Mussinae. Fossil specimens are selected from a large well-documented collection of Neogene Caribbean corals, and a total of 23 species are distinguished using 15 morphological features. Ten of the 23 species are extant Caribbean species, seven are previously described extinct Neogene species, and six other extinct species are formally described as new. The 7 + 6 extinct species are added to a morphological data set consisting of 30 extant molecularly characterized species plus seven additional extinct (five Eocene, two Neogene) species. In addition to the Caribbean subfamily Mussinae, the extant species include the Indo-Pacific families Merulinidae and Lobophylliidae, and the Caribbean subfamily Faviinae. Phylogenetic analysis was performed on the data using maximum parsimony, and the results reveal four clades, which correspond with previously reported molecular clades. Solitary corals group most closely with Caribbean Mussinae and Indo-Pacific Lobophylliidae, whereas colonial corals are present in all four clades. Within Caribbean Mussinae, members of the colonial genera Mycetophyllia and Isophyllia form distinct subclades, as do the extinct solitary genera Antillia and Antillophyllia. The relationships within Scolymia are less well defined but its members appear more closely related to extinct solitary genera dating back to the Eocene. These results indicate that evolutionary transitions between solitary and colonial corals have been rare within the Mussinae. Except Antillophyllia, most Mussinae genera are restricted to the Caribbean. During the late Miocene, Mycetophyllia diversified and three other modern Mussinae genera (Mussa, Scolymia, Isophyllia) originated in association with increased Caribbean productivity. Mussinae that were more likely to survive Plio–Pleistocene extinction may have taken refuge in deep forereef habitats.

Ancient DNA provides a powerful window into the biology of extant and extinct species, including humans’ closest relatives: Denisovans and Neanderthals. Here, we review what is known about archaic hominin phenotypes from genomic data and how those inferences have been made. We contend that understanding the influence of variants on lower-level molecular phenotypes—such as gene expression and protein function—is a promising approach to using ancient DNA to learn about archaic hominin traits. Molecular phenotypes have simpler genetic architectures than organism-level complex phenotypes, and this approach enables moving beyond association studies by proposing hypotheses about the effects of archaic variants that are testable in model systems. The major challenge to understanding archaic hominin phenotypes is broadening our ability to accurately map genotypes to phenotypes, but ongoing advances ensure that there will be much more to learn about archaic hominin phenotypes from their genomes.

Seismic stratigraphy of the Blue Hole (Lighthouse Reef, Belize), a late Holocene climate and storm archive

The remains of six species of geese are commonly recovered from archaeological sites in Britain dating from the Saxon and later periods. However, identification of this material to species level is hampered by a lack of morphological variation and a large overlap in size. To address this issue we obtained DNA sequence data for a section of the mitochondrial cytochrome b gene from modern samples of each species, and successfully identified several DNA markers for Branta species. No markers were found within the cytochrome b gene for the genus Anser. Ancient DNA techniques were then used to recover DNA from goose bones excavated from two archaeological sites. The DNA sequences enabled identification of Barnacle goose (Branta leucopsis) from one site and confirmed the presence of Anser species at another. © 1998 John Wiley & Sons, Ltd.

The soft coral genus Alcyonium is among the most reproductively diverse invertebrate taxa known: The genus includes species that vary both in mode of reproduction (including broadcast spawners, internal brooders, and external brooders) and sexual expression (gonochores, hermaphrodites, and a unisexual parthenogen). Such diversity offers a unique opportunity to examine associations between reproductive and morphological traits in a phylogenetic context. We used an approximately 900-bp sequence of the nuclear ribosomal gene complex spanning the internal transcribed spacer (ITS) regions to construct a molecular phylogeny for 14 European and North American species of Alcyonium onto which we mapped the known distribution of reproductive and morphological traits. The phylogeny suggests that hermaphroditism or parthenogenesis has evolved independently at least twice in this genus, and always in internally brooding species. Broadcast spawning and external brooding only occur in species with large colony size, whereas all species with small colony size brood their larvae internally. Internal brooding and small size appear to be ancestral in this genus; if this is the case, an association between broadcast spawning and large colony size has evolved independently in at least two clades. This tendency of small adults to brood their larvae while large adults broadcast spawn them into the plankton has been observed in a variety of solitary invertebrate taxa, but to date has not been documented in any other colonial invertebrates. Moreoever, it has been suggested that organisms with a colonial growth form should not experience the allometric constraints on brood space that have been proposed to explain the association between adult size and mode of reproduction in solitary organisms. Unlike many other colonial groups, however, module (polyp) size is strongly correlated with colony size in Alcyonium, and constraints on brooding may be imposed by module, rather than colony, allometry. The very close genetic relationship (< 1% sequence divergence) and shared polymorphisms among A. digitatum (a large, gonochoric broadcast spawner), A. siderium, and A. sp. A (intermediate-sized and small hermaphroditic, internal brooders) suggest that evolutionary transitions between broadcast spawning and brooding and between gonochorism and hermaphroditism can occur easily and rapidly in this group.

Digging deeper into the limits of ancient DNA research on syphilis

The ability to predict ancient DNA sequencing success in natural history collections is critical to reducing the amount of destructive sampling of a finite resource. So far, studies investigating such success have predominantly focused on taxa with ranges restricted to temperate or cold environments at northern latitudes, which likely aids DNA preservation. Here, we report remarkably high aDNA sequencing success in Sirenia, herbivorous marine mammals of which the distribution is currently constrained to the global tropics. We investigate 91 samples from 85 specimens comprising all four contemporary species and one extinct species, comparing different sample types (cranial/post-cranial bone, skin and cartilage), species, collections, and material age. We obtained remarkably high (e.g., > 20%) endogenous DNA preservation for the majority (e.g., ~57% percent) of samples. Sequencing success was linked to sample type, with cranial bones (including petrous and tympanic bones) yielding significantly higher endogenous DNA. Additionally, we obtained variable, but potentially superior DNA results for preserved cartilage and hide samples that can be associated with historical bone. Although such tissue is not always present, this type of material is easy to sample, with very limited destructive impacts on the associated bones, and we therefore highlight its untapped potential as a source of DNA. Overall, our results show the high success of ancient DNA retrieval from historical collections of species with a tropical distribution, expanding on the types of specimens that are available for temporal genomic analyses.

DNA analyses of wild boar remains from archaeological sites in Guangxi, China