Diversität und Evolution Antarktischer Gastropoden: ein genomischer Ansatz

南极无脊椎动物似乎高度多样化，但只是局部的和零星的探索--并且已经受到全球气候变化的威胁。腹足类资源丰富，物种丰富，具有重要的生态和经济意义，有化石记录，是许多科学学科的S模式生物。大约600种南极腹足类物种中的大多数在早上被认为是有效的，这是基于通常只有几个或单一样本的贝壳特征。种内形态变异、软相似解剖、生物学和生态学通常是未知的，许多同义词已经被提出。分子数据仅限于较常见物种的少数个体的CÖi条形码序列：对单个基因的系统发育分析表明，存在复杂的隐蔽物种或深层谱系，这可能显示出不同的地理分布和特殊的生态位。物种或样本的稀缺性阻碍了一般的群体遗传学方法。我们提出的项目的首要目标是全面、可靠地揭示南极腹足动物的物种多样性。除了线粒体CÖI外，我们还将使用下一代测序(NGS)和新建立的方法(双酶切限制相关DMA测序，ddRADseq)来有效地产生大量独立的核基因组序列标记。我们将包括ZSM软体动物收藏中适用于基因研究的2000多个南奥塞腹足类样本的所有物种和亚样本，以及将在探险队或其他博物馆收集的更多材料。我们将进行系统发育分析(最好的ML、贝叶斯、亚组)和组合的、最新的分子物种划分方法(ABGD、GMYCS BP&P)，将应用依赖于同余的综合分类方法来揭示！保守和可靠的进化物种单位，将用于多样性分析，我们还将探索进行化石校准的野兽年代图的腹足类世系的基因组进化档案。多样化的动态将通过最近的出生-死亡-转移模型进行分析，历史生物地理学将使用最近的软件(例如，RASP)重建。利用我们来自许多亚类群的基因组数据，我们将检验当前的生物地理学和进化范式，例如导致“南极物种形成泵”的S冰川周期，并评估关于冰川避难所和迁徙情景的相互竞争的假说。这里提出的ddRADseq与最新的多中心分析相结合的方法是新颖的，极具成本和时间效益，并且可以包括数千个而不是几个样本？而不需要任何先验的选择加速器。预计它将非常强大地划定Newty收集的、未识别的或神秘的物种，即使JF采样不佳或仅由单个实例表示。我们相信，这种方法是一次巨大的飞跃，涉及到对偏远和高度多样的动物群的探索，因此，我们的开创性项目将产生大量新颖和全面的南极腹足类数据和结果，这些数据和结果可能会改变之前对生物地理学或生态学的看法，这些观念几乎完全依赖于定义模糊的“形态种”概念，最终，进化物种单位将从形态、地理和生态角度进行特征描述。这将成为未来研究过去进化适应、生态位形成和预测对全球变化和海洋酸化反应的基础。

The Antarctic irwertebrate fauna appears highiy diverse, but is only localiy and sporadically explored - and already threatened by global climate change. Gastropods are abundant, species rieh, ecologically and economically irnportant, count with a rieh fossil record and are wellestablished äs model organisms for many scientific disciplines. Most of the roughly 600 Antarctic gastropod species are regarded valid at the mornent based on shell features of often just a few or single specimens. Intraspecific morphological variability, soft pari anatomy, biology» and ecology are usually unknown, and many synonyms have been proposed. Wolecular data are limited to CÖI barcode sequences of few individuals of the more common species: Phylogenetic analyses of single genes suggest complexes of cryptic species or deep lineages, which may show distinct geographic distributions and special ecological niches. Rarity of species or samples prohibits general population genetics approaches. The prirnary goal of our herein proposed project is revealing the species diversity of Antarctic gastropods comprehensively and reliably. In addition to mltochondrial CÖI, we will use next generation sequencing (NGS) and newly established methods (double digest Restriction Associated DMA sequencing, ddRADseq) to efficiently generate a multitude of independent nuclear genomic sequence markers. We will include all species and subsamples from rnore than 2000 Southern Öcean gastropod samples available at the ZSM Mollusca collection suitable for genetic studies, plus further material to be collected at expeditions or from other museums. We will perform phylogenetic analyses (ML, Bayes, in subgroups BEST) and combined, up~to-date molecular species delimitation approaches {ABGD, GMYCS BP&P), An integrative taxonomic approach reiying on congruence will be applied to revea! conservative and reliable evolutionary species units, which will be used for diversity analyses, We will also explore genomic evolutionary archives of seiected gastropod lineages performing fossil-calibrated BEAST chronograms. The dynamics of diversification will be analyzed via recent Birth-Death-Shift models, and historical biogeography will be reconstructed using recent Software (e.g, RASP). With our massif genomic data from many subtaxa we will test current paradigms on biogeography and evolution, such äs glacial cycles causing an "Antarctic speciation pump", and evaluate competing hypotheses on glacial refuges and migration scenarios. The herein proposed combination of ddRADseqs with up~to~date multi-iocus analyses is novel, extremely cost and time effective, and can include thousands instead of few specimens» without any a priori selectron. It is expected to be very powerful to delimitate newty collected, unrecognized, or cryptic species, even jf badly sampled or just represented by singletons. We trust this approach is a quantum leap forward referring to the exploration of remote and highiy diverse faunas, Our pioneer project thus will generate massif novel and comprehensive data and results on Antarctic gastropods which might change previous ideas on e.g. biogeography or ecology, that aimost entirely relted on ill-defined „morphospecies" concepts, Eventually, evolutionary species units will be characterized morphologically, geographicaliy and ecologically. This will be the basis for future studies on past evolutionary adaptations, ecological niche rnodelling, and predicting response to global change and ocean acidification.