A tale of textiles: Genetic characterization of historical paper mulberry barkcloth from Oceania.

Humans introduced paper mulberry (Broussonetia papyrifera) from Taiwan into the Pacific over 5000 years ago as a fiber source to make barkcloth textiles that were, and still are, important cultural artifacts throughout the Pacific. We have used B. papyrifera, a species closely associated to humans, as a proxy to understand the human settlement of the Pacific Islands. We report the first genetic analysis of paper mulberry textiles from historical and archaeological contexts (200 to 50 years before present) and compare our results with genetic data obtained from contemporary and herbarium paper mulberry samples. Following stringent ancient DNA protocols, we extracted DNA from 13 barkcloth textiles. We confirmed that the fiber source is paper mulberry in nine of the 13 textiles studied using the nuclear ITS-1 marker and by statistical estimates. We detected high genetic diversity in historical Pacific paper mulberry barkcloth with a set of ten microsatellites, showing new alleles and specific genetic patterns. These genetic signatures allow tracing connections to plants from the Asian homeland, Near and Remote Oceania, establishing links not observed previously (using the same genetic tools) in extant plants or herbaria samples. These results show that historic barkcloth textiles are cultural materials amenable to genetic analysis to reveal human history and that these artifacts may harbor evidence of greater genetic diversity in Pacific B. papyrifera in the past.

Human mediated translocation of Pacific paper mulberry [Broussonetia papyrifera (L.) L'Hér. ex Vent. (Moraceae)]: Genetic evidence of dispersal routes in Remote Oceania.

Paper mulberry, Broussonetia papyrifera (L.) L'Hér. ex Vent. (Moraceae), a dioecious species, was transported by humans from Taiwan to the islands of Remote Oceania. Its introduction and cultivation in Remote Oceania was intentional due to its cultural importance as a fiber source for barkcloth textiles. The aim of this study was to explore the genetic diversity and structure of paper mulberry populations within Remote Oceania in order to infer dispersal patterns that may reflect past human interaction among island groups. We present the integrated analysis of 380 samples (313 contemporary and 67 herbarium specimens) collected in Near and Remote Oceania. Genetic characterization was based on a set of ten microsatellites developed for B. papyrifera and complemented with the analysis of the ribosomal internal transcribed spacer ITS-1 sequence, a sex marker and the chloroplast ndhF-rpl32 intergenic spacer. Microsatellite data identify a total of 64 genotypes, despite this being a clonally propagated crop, and show three major dispersal hubs within Remote Oceania, centered on the islands of Fiji, Tonga, and Pitcairn. Of 64 genotypes identified, 55 correspond to genotypes associated to female-sexed plants that probably descend from plants introduced by the prehistoric Austronesian-speaking voyagers. The ratio of accessions to genotypes between herbarium and contemporary samples, suggests recent loss of genetic diversity. In addition to the chloroplast haplotypes described previously, we detected two new haplotypes within Remote Oceania both originating in Taiwan. This is the first study of a commensal species to show genetic structuring within Remote Oceania. In spite of the genetic bottleneck, the presence of only one sex, a timespan of less than 5000 years, and asexual propagation of this crop in Remote Oceania, we detect genetic diversity and regional structuring. These observations suggest specific migration routes between island groups within Remote Oceania.

Characterization of microsatellite markers for Broussonetia papyrifera (Moraceae).

PREMISE OF THE STUDY: Broussonetia papyrifera (Moraceae) is native to Asia and is used as a medicinal plant and as a source of fiber for making paper. It was dispersed into the Pacific region as a fiber source for making nonwoven textiles (barkcloth). Microsatellites were developed to trace the human-mediated dispersal of this species into the Pacific region. METHODS AND RESULTS: A set of 36 microsatellites was isolated and initially assayed on 10 accessions to assess polymorphism. We found that 20 markers were polymorphic, with the number of alleles per marker ranging from four to 35 in 70 accessions genotyped from three Asian populations. Observed and expected heterozygosities ranged from 0.04 to 0.85 and from 0.19 to 0.94, respectively. These markers were tested in four Moraceae species and one Rosaceae species. CONCLUSIONS: These markers will be useful for the assessment of genetic diversity in B. papyrifera. They show low transferability to other species tested.

Phylogeography of herbarium specimens of asexually propagated paper mulberry [Broussonetia papyrifera (L.) L'Hér. ex Vent. (Moraceae)] reveals genetic diversity across the Pacific.

Background and Aims: Paper mulberry or Broussonetia papyrifera (L.) L'Hér. ex Vent. (Moraceae) is a dioecious species native to continental South-east Asia and East Asia, including Taiwan, that was introduced to the Pacific by pre-historic voyagers and transported intentionally and propagated asexually across the full range of Austronesian expansion from Taiwan to East Polynesia. The aim of this study was to gain insight into the dispersal of paper mulberry into Oceania through the genetic analysis of herbaria samples which represent a more complete coverage of the historical geographical range of the species in the Pacific before later introductions and local extinctions occurred. Methods: DNA from 47 herbarium specimens of B. papyrifera collected from 1882 to 2006 from different islands of the Pacific was obtained under ancient DNA protocols. Genetic characterization was based on the ribosomal internal transcribed spacer ITS-1 sequence, a sex marker, the chloroplast ndhF-rpl32 intergenic spacer and a set of ten microsatellites developed for B. papyrifera. Key Results: Microsatellites allowed detection of 15 genotypes in Near and Remote Oceanian samples, in spite of the vegetative propagation of B. papyrifera in the Pacific. These genotypes are structured in two groups separating West and East Polynesia, and place Pitcairn in a pivotal position. We also detected the presence of male plants that carry the Polynesian chloroplast DNA (cpDNA) haplotype, in contrast to findings in contemporary B. papyrifera populations where only female plants bear the Polynesian cpDNA haplotype. Conclusions: For the first time, genetic diversity was detected among paper mulberry accessions from Remote Oceania. A clear separation between West and East Polynesia was found that may be indicative of pulses during its dispersal history. The pattern linking the genotypes within Remote Oceania reflects the importance of central Polynesia as a dispersal hub, in agreement with archaeological evidence.

Sex Distribution of Paper Mulberry (Broussonetia papyrifera) in the Pacific.

BACKGROUND: Paper mulberry (Broussonetia papyrifera (L.) L'Hér. ex Vent) is a dioecious tree native to East Asia and mainland Southeast-Asia, introduced prehistorically to Polynesia as a source of bark fiber by Austronesian-speaking voyagers. In Oceania, trees are coppiced and harvested for production of bark-cloth, so flowering is generally unknown. A survey of botanical records of paper mulberry revealed a distributional disjunction: the tree is apparently absent in Borneo and the Philippines. A subsequent study of chloroplast haplotypes linked paper mulberry of Remote Oceania directly to a population in southern Taiwan, distinct from known populations in mainland Southeast-Asia. METHODOLOGY: We describe the optimization and use of a DNA marker designed to identify sex in paper mulberry. We used this marker to determine the sex distribution in selected localities across Asia, Near and Remote Oceania. We also characterized all samples using the ribosomal internal transcribed spacer sequence (ITS) in order to relate results to a previous survey of ITS diversity. RESULTS: In Near and Remote Oceania, contemporary paper mulberry plants are all female with the exception of Hawaii, where plants of both sexes are found. In its natural range in Asia, male and female plants are found, as expected. Male plants in Hawaii display an East Asian ITS genotype, consistent with modern introduction, while females in Remote Oceania share a distinctive variant. CONCLUSIONS: Most paper mulberry plants now present in the Pacific appear to be descended from female clones introduced prehistorically. In Hawaii, the presence of male and female plants is thought to reflect a dual origin, one a prehistoric female introduction and the other a modern male introduction by Japanese/Chinese immigrants. If only female clones were dispersed from a source-region in Taiwan, this may explain the absence of botanical records and breeding populations in the Philippines and Borneo, and Remote Oceania.

DNA extraction and amplification from contemporary Polynesian bark-cloth.

BACKGROUND: Paper mulberry has been used for thousands of years in Asia and Oceania for making paper and bark-cloth, respectively. Museums around the world hold valuable collections of Polynesian bark-cloth. Genetic analysis of the plant fibers from which the textiles were made may answer a number of questions of interest related to provenance, authenticity or species used in the manufacture of these textiles. Recovery of nucleic acids from paper mulberry bark-cloth has not been reported before. METHODOLOGY: We describe a simple method for the extraction of PCR-amplifiable DNA from small samples of contemporary Polynesian bark-cloth (tapa) using two types of nuclear markers. We report the amplification of about 300 bp sequences of the ITS1 region and of a microsatellite marker. CONCLUSIONS: Sufficient DNA was retrieved from all bark-cloth samples to permit successful PCR amplification. This method shows a means of obtaining useful genetic information from modern bark-cloth samples and opens perspectives for the analyses of small fragments derived from ethnographic materials.

Genetic diversity and geographical dispersal in grapevine clones revealed by microsatellite markers.

Intravarietal genetic diversification associated with geographical dispersal of a vegetatively propagated species was studied using grapevine Vitis vinifera L. 'Cabernet Sauvignon' as a model. Fifty-nine clonal samples obtained from 7 countries (France, Chile, Spain, Australia, Hungary, USA, and Italy) were analyzed using 84 microsatellite markers. Eighteen polymorphic microsatellite loci (21.4%) were detected, finding 22 different genotypes in the population analyzed with a genetic similarity of over 97%. The presence of chimeric clones was evidenced at locus VMC5g7 by means of a segregation analysis of descendants by self-pollination of a triallelic Chilean clone and by somatic embryogenesis analysis, showing a mutation in L2 cell layer. Only 2 clones (obtained from France and Australia) presented the ancestral genotype, and the most divergent genotype was exhibited by another French clone, which had accumulated 5 somatic mutations. The 2 largest populations considered (from France and Chile) showed a clear divergency in the polymorphisms detected. These antecedents enabled the tracing of geographical dispersal with a phylogenetic hypothesis supporting France as the center of origin of diversification of Cabernet Sauvignon. The results obtained could help to explain diversification processes in other grapevine cultivars. The possibility that this kind of genetic variability occurs in other vegetatively propagated species is discussed, focusing on possible fingerprinting applications.