25 research outputs found

    DNA methylation levels in candidate genes associated with chronological age in mammals are not conserved in a long-lived seabird

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    © 2017 De Paoli-Iseppi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Most seabirds do not have any outward identifiers of their chronological age, so estimation of seabird population age structure generally requires expensive, long-term banding studies. We investigated the potential to use a molecular age biomarker to estimate age in short-tailed shearwaters (Ardenna tenuirostris). We quantified DNA methylation in several A. tenuirostris genes that have shown age-related methylation changes in mammals. In birds ranging from chicks to 21 years of age, bisulphite treated blood and feather DNA was sequenced and methylation levels analysed in 67 CpG sites in 13 target gene regions. From blood samples, five of the top relationships with age were identified in KCNC3 loci (CpG66: R2 = 0.325, p = 0.019). In feather samples ELOVL2 (CpG42: R2 = 0.285, p = 0.00048) and EDARADD (CpG46: R2 = 0.168, p = 0.0067) were also weakly correlated with age. However, the majority of markers had no clear association with age (of 131 comparisons only 12 had a p-value < 0.05) and statistical analysis using a penalised lasso approach did not produce an accurate ageing model. Our data indicate that some age-related signatures identified in orthologous mammalian genes are not conserved in the long-lived short tailed shearwater. Alternative molecular approaches will be required to identify a reliable biomarker of chronological age in these seabirds

    Sociophonetic variation in a long-term language contact situation: /l/-darkening in Welsh-English bilingual speech

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    This study investigates /l/-darkening in the Welsh and English speech of bilinguals in North Wales. Although it is claimed that /l/ is dark in all syllable positions in northern varieties of both languages, there have been no quantitative investigations of this feature which consider cross-linguistic phonetic differences, the differing nature of language contact between North East and North West Wales, and differences in the way both languages are acquired by speakers. The dataset of 32 Welsh-English bilinguals, aged 16-18, was stratified by speaker sex, home language, and area. Tokens of /l/ in word-initial onset and word-final coda positions were analysed acoustically. The results show cross-linguistic differences in onset position and that such differences were found to be greater in the speech of female participants and those from North West Wales. Differences were also found between Welsh-dominant and English-dominant communities. These results are discussed with reference to the influence of extra-linguistic factors on speech production and the possible social meaning associated with dark /l/

    First comprehensive peat depositional records for tin, lead and copper associated with the antiquity of Europe's largest cassiterite deposits

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    Tin, as a constituent of bronze, was central to the technological development of early societies, but cassiterite (SnO<sub>2</sub>) deposits were scarce and located distantly from the centres of Mediterranean civilizations. As Britain had the largest workable ore deposits in the ancient Western world, this has led to much historical speculation and myth regarding the long-distance trading of tin from the Bronze Age onwards. Here we establish the first detailed chronology for tin, along with lead and copper deposition, into undisturbed ombrotrophic (rain-fed) peat bogs located at Bodmin Moor and Dartmoor in the centre of the British tin ore fields. Sustained elevated tin deposition is demonstrated clearly, with peaks occurring at 100–400 and 700–1000 calendar years AD – contemporaneous with the Roman and Anglo-Saxon periods respectively. While pre-Roman Iron Age tin exploitation undoubtedly took place, it was on a scale that did not result in convincingly enhanced deposition of the metal. The deposition of lead in the peat record provides evidence of a pre-Roman metal-based economy in southwest Britain. Emerging in the 4th century BC, this was centred on copper and lead ore processing that expanded exponentially and then collapsed upon Roman colonization during the 1st century AD
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