Browsing by Issue Date, starting with "2022-10-13"
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- Non-invasive prospection methods in the Roman City of Balsa (Luz de Tavira-Portugal): revealing the real townscapePublication . BERNARDES, João Pedro; Sevilla, Isabel Rondán; Candeias, Celso; Barroso, Manuel RuizEver since Estácio da Veiga, at the end of the 19th century, identified the ruins of the Roman city of Balsa under Torre d’Aires estate (Luz de Tavira-Portugal) and its surroundings, the scientific questions about this Roman city have been constantly increasing. Despite the historical importance of this city, referenced in classical literature, the archaeological knowledge about it remains very scarce due to the difficulties around implementing any durable scientific research projects. Therefore, much of that written about the topographical features and configuration of the city has no unequivocal scientific support. Finally, 2019 saw the launch of this ongoing project “Balsa, searching for the origins of the Algarve”, which aims to ascertain the main features concerning the city’s extent and configuration, mainly through non-invasive methods. Since 2017, geomagnetic and geo-radar surveys have spanned several hectares and successfully identified many traces of the Roman city while discarding the existence of others in certain locations. In the last two years, the geo-radar surveys have intensified and established the boundaries to the Roman city as well as parts of its layout, remnants of buildings, and even fossilised agricultural crops in addition to other geophysical anomalies, whether or not they are subsequently confirmed by diagnostic pits.
- Population genomics of an icefish reveals mechanisms of glacier-driven adaptive radiation in Antarctic notothenioidsPublication . Lu, Ying; Li, Wenhao; Li, Yalin; Zhai, Wanying; Zhou, Xuming; Wu, Zhichao; Jiang, Shouwen; Liu, Taigang; Wang, Huamin; Hu, Ruiqin; Zhou, Yan; Zou, Jun; Hu, Peng; Guan, Guijun; Xu, Qianghua; Canario, Adelino; Chen, LiangbiaoBackground Antarctica harbors the bulk of the species diversity of the dominant teleost fish suborder—Notothenioidei. However, the forces that shape their evolution are still under debate. Results We sequenced the genome of an icefish, Chionodraco hamatus, and used population genomics and demographic modelling of sequenced genomes of 52 C. hamatus individuals collected mainly from two East Antarctic regions to investigate the factors driving speciation. Results revealed four icefish populations with clear reproduction separation were established 15 to 50 kya (kilo years ago) during the last glacial maxima (LGM). Selection sweeps in genes involving immune responses, cardiovascular development, and photoperception occurred differentially among the populations and were correlated with population-specific microbial communities and acquisition of distinct morphological features in the icefish taxa. Population and species-specific antifreeze glycoprotein gene expansion and glacial cycle-paced duplication/degeneration of the zona pellucida protein gene families indicated fluctuating thermal environments and periodic influence of glacial cycles on notothenioid divergence. Conclusions We revealed a series of genomic evidence indicating differential adaptation of C. hamatus populations and notothenioid species divergence in the extreme and unique marine environment. We conclude that geographic separation and adaptation to heterogeneous pathogen, oxygen, and light conditions of local habitats, periodically shaped by the glacial cycles, were the key drivers propelling species diversity in Antarctica.