重新评估Haarlem Archeopteryx和Maniraptoran theropod恐龙的辐射

It is 1861 and Hermann von Meyer, a German paleontologist, inspects a slab of Bavarian limestone depicting a single feather. He will name this specimen archaeopteryx, signifying an “ancient wing” or “feather”.

The same year, the first Archaeopteryx skeleton was discovered, depicting what was to be considered the oldest known ancestor of the modern bird for decades to come. Marking the boundary between bird and dinosaur, this iconic fossil has been pivotal to our understanding of avian evolution.

在这项研究中，作者重新检查了目前位于哈勒姆的Teylers博物馆的Archeopteryx最不完整的标本之一。在进行解剖学分析之后，他们得出结论，“ Haarlem标本”更有可能来自中国锚固，这是一群早于大型近代的有翼的恐龙。

This study has had fascinating implications for our understanding of the origins of modern birds. The authors propose a westward spread of the avian ancestors from their origins in East Asia and arriving in Bavaria, where their remains would be found 350 million years later.

A new species of Xenoturbella from the western Pacific Ocean and the evolution of Xenoturbella

从灭绝到现存，我们继续发现一种新的异种外url虫。真正奇怪的海洋生物。直到最近，这种神秘的生物才被收集在瑞典沿海的海洋中。

遗弃在海床上的旧袜子，将异种斗犬误认为是不难的。它的形态非常简单，其行为习惯未知。在近年来，即使是其系统发育位置也激烈地争论。

也许异种外虫最定义的特征是缺乏肛门和缺乏集中的神经系统。它的嘴是可以交换食物和废物的单一开口。这些非凡的特征使其成为研究这些特征的进化起源的吸引人选择。

发表的论文BMC Evolutionary Biologythis year reports the identification of a new species of Xenoturbella in the Western Pacific Ocean off the coast of Japan. It is relatively easily collected via marine biology dredge and thus holds a lot of promise as a research organism for the further characterization of this strange species.

达尔文雀科的城市和农村人口之间的表观遗传变化

周游的远端the Pacific Ocean, the authors of our next paper go to the Galapagos Islands to study Darwin’s finches. These birds are best known for helping shape Charles Darwin’s theory of natural selection. There are 16 species native to the Galapagos islands, each most clearly identified by their differing beak sizes and shapes that are adapted to the different food sources found on each island.

Nearly 160 years later, the field of epigenetics may provide an explanation for the rapid adaptation that these finches display. Epigenetics refers to the study of changes in gene expression rather than the genetic code, achieved through modifications of DNA by processes such as methylation.

DNA甲基化描述了在核苷酸中添加碳和三个氢原子，然后在鸟嘌呤中以“ CpG”阶段添加。一些甲基化模式已被证明是可遗传的，而甲基化模式甚至显示出高于遗传密码中观察到的突变速率。至关重要的是，对于这项研究，据报道，环境会影响DNA甲基化模式。

这表明表观遗传学可能有助于每种达尔文雀科中的快速表型变化。但是，可能发生的过程仍然未知。

After studying two species of finch, the authors reported significant differences in methylation patterns between urban and rural populations of each species. Urbanization in the Galapagos Islands has happened within the last 60 years, so while the authors are careful to acknowledge the possibility of random epigenetic drift, if urbanization is the cause for these differences in methylation then these changes have occurred impressively quickly.

A genetic chronology for the Indian Subcontinent points to heavily sex-biased dispersals

我们的下一项研究检查了线粒体DNA，以确定现代印度人口的古老血统。在200,000到400，000年前，人们认为解剖学上的现代人类已经迁出东非并穿越了印度次大陆，因此使印度人口成为地球上最多样化的人口之一。

但是，印度人口的遗传研究并非易事。由于种姓制度施加的僵化的社会界限，高水平的内婚是常见的。这些社会孤立的人群之间的遗传密码（称为遗传漂移）的变化。

也许最有趣的是，大约4000年前，来自中亚的人们的运动为古老的印度 - 欧洲语言传播到印度提供了新的证据。

The authors of this study aimed to remedy these problems by tracing the inheritance of mitochondrial DNA, which is exclusively maternally inherited as well as DNA found exclusively on the Y chromosome, which is exclusively passed down the male line. This allows lineages to be traced for millennia back in time. In combination with genome wide analyses, ancient immigration patterns were able to be deduced.

The theory proposing an “Indo-Aryan invasion” to India is highly controversial. It has the potential to explain the presence of Indo-European languages, spoken across the northern half of India, while some have also attributed the origins of the caste system to this hypothetical event. Previously, there had been no archaeological data or genetic data to support any claims this event may have occurred.

本文提出的是在50，000年内从伊朗，高加索和安纳托利亚的一系列移民浪潮。也许最有趣的是，大约4000年前，来自中亚的人们的运动为古老的印度 - 欧洲语言传播到印度提供了新的证据。

Skeptics have pointed to the lack of ancient preserved DNA in South Asia to confirm any migration occurred. This study does, however, provide an exciting new perspective on this often disputed topic.

Going deeper in the automated identification of Herbarium specimens

The final study in our end of year selection focuses on the use of artificial intelligence to identify new species of plant. Vast numbers of preserved plant specimens have been increasingly archived in a digital format and placed online in publicly available databases.

随着当代对植物系统发育和进化的理解，我们对植物物种的了解变得过时，必须修改数据条目。世界各地的草药中存储了大约3.5亿个标本。这大量数据意味着这对仅仅是凡人而言并不是合适的任务。

今年，Carranza-Rojas等人设计了一种算法，旨在使用深度学习来根据保存的植物标本的数字图像来识别植物物种。该软件能够在90％的前5个结果中生产正确的植物物种，而正确的结果是70％的病例中的第一次命中。

深度学习技术在植物学领域显示出巨大的希望，并有可能彻底改变植物识别。我们期待进一步的研究和新的突破性，并在数字时代迎来了下一代软件。