《科学》（20190315出版）一周论文导读

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《科学》（20190315出版）一周论文导读

2019 年 3 月 15 日 科学网

翻译 | 唐一尘

Science, 15 MARCH 2019, VOL 363, ISSUE 6432

《科学》2019年3月15日，第6432期363卷

古人类Paleoanthropology

Human sound systems are shaped by post-Neolithic changes in bite configuration

人类声音系统是由新石器时代以后的咬合结构变化所形成的

▲ 作者：D. E. Blasi、S.Moran、S. R. Moisik、P. Widmer、D. Dediu、B. Bickel

▲ 链接：

http://science.sciencemag.org/content/363/6432/eaav3218

▲ 摘要：

人类语言变化范围从普遍存在的“m”和“a”音至南部非洲某些语言中存在的罕见的搭嘴音。然而，这一声音范围一般被认为是随着智人在约30万年前的出现而确立的，它们与从那以后的人类任何生物学变化无关。

本研究报告称，诸如“f”和“v”这样的声音虽然在许多现代语言中皆属常见，但却是在相对近来的时候发展而成的，即由饮食诱导的人类对食物撕咬方式改变产生的。

研究人员通过包括对不同人类口面部构造进行详细的生物力学模拟等研究证明，成人牙齿结构的保持其上齿相对于下齿的略微靠前的变化（这一变化与诸如工业化碾磨等食物加工技术的出现时间吻合）导致了一类新语音的出现。

这类被称作唇齿音的声音通过将下唇与上齿接触而产生的，如今出现于半数的世界语言中。

▲ Abstract

Linguistic diversity, now and in the past, is widely regarded to be independent of biological changes that took place after the emergence of Homo sapiens. We show converging evidence from paleoanthropology, speech biomechanics, ethnography, and historical linguistics that labiodental sounds (such as “f” and “v”) were innovated after the Neolithic. Changes in diet attributable to food-processing technologies modified the human bite from an edge-to-edge configuration to one that preserves adolescent overbite and overjet into adulthood. This change favored the emergence and maintenance of labiodentals. Our findings suggest that language is shaped not only by the contingencies of its history, but alsoby culturally induced changes in human biology.

The genomic history of the Iberian Peninsula over the past 8000 years

伊比利亚半岛过去8000年的基因组历史

▲ 作者：Iñigo Olalde、Swapan Mallick、Nick Patterson、David Reich，et al

▲ 链接：

http://science.sciencemag.org/content/363/6432/1230

▲ 摘要：

研究古代DNA可以了解古人的流动迁徙，它已成为拓宽人们对全球生物地理学了解以及基因混合如何促成了当代的人群与文化的日益有用的工具。

伊比利亚半岛位处北非、欧洲与地中海之间，有着与周围地区长期互动的历史，它为弄清人类从地中海东部和北非向欧洲大陆内迁徙的基因学影响提供了理想的机会。

本研究集合了271个古代伊比利亚人的全基因组数据并创建一个跨越近8000年的进入并充斥该地区的基因流向综合年表。

结果显示，该地区中石器时代的狩猎采集者的人口结构比先前认为的要复杂得多。研究人员还发现距今约2500年时伊比利亚半岛人早期与北非人的互动。

这些结果还揭示了从东方的东欧大草原的人类移民所造成的巨大冲击——到距今约2000年时，有近40%的伊比利亚血统和近100%的当地男性群体被来自草原的人的血统所替换。

▲ Abstract

We assembled genome-wide data from 271 ancient Iberians, of whom 176 are from the largely unsampled period after 2000 BCE, thereby providing a high-resolution time transect of the Iberian Peninsula. We document high genetic substructure between northwestern and southeastern hunter-gatherers before the spread of farming. We reveal sporadic contacts between Iberia and North Africa by ~2500 BCE and, by ~2000 BCE, the replacement of 40% of Iberia’s ancestry and nearly 100% of its Y-chromosomes by people with Steppe ancestry. We show that, in the Iron Age, Steppe ancestry had spread not only into Indo-European–speaking regions but also into non-Indo-European–speaking ones,and we reveal that present-day Basques are best described as a typical Iron Age population without the admixture events that later affected the rest of Iberia. Additionally, we document how, beginning at least in the Roman period, the ancestry of the peninsula was transformed by gene flow from North Africa and the eastern Mediterranean.

生态Ecology

The oceanic sink for anthropogenic CO₂ from 1994 to 2007

1994年至2007年人为二氧化碳的海洋储量

▲ 作者：Nicolas Gruber、Dominic Clement、Brendan R. Carter、Richard A. Feely，et al

▲ 链接：

http://science.sciencemag.org/content/363/6432/1193

▲ 摘要：

本研究利用全球重复水文计划的观测资料，并将其与上世纪90年代的观测结果进行对比，对1994年至2007年间的人为二氧化碳海洋汇进行了量化。

采用基于线性回归的方法，我们发现，1994年至2007年间，全球人为二氧化碳海洋存量增加了34±4十亿吨碳(Pg C)。这相当于平均每年吸收2.6±0.3 Pg C，占同期全球人为二氧化碳排放的31±4%。

虽然这一全球海洋碳汇估计数与海洋吸收随大气二氧化碳增加而增加的预期相符，但研究发现储藏率有很大的区域差异，这可能是由于气候变化引起的海洋环流的变化。

▲ Abstract

We quantify the oceanic sink for anthropogenic carbon dioxide (CO₂) over the period 1994 to 2007 by using observations from the global repeat hydrography program and contrasting them to observations from the1990s. Using a linear regression–based method, we find a global increase in the anthropogenic CO₂ inventory of 34 ± 4 petagrams of carbon (PgC) between 1994 and 2007. This is equivalent to an average uptake rate of 2.6 ±0.3 Pg C year⁻¹ and represents 31 ± 4% of the global anthropogenic CO₂ emissions over this period. Although this global ocean sink estimate is consistent with the expectation of the ocean uptake having increased in proportion to the rise in atmospheric CO₂, substantial regional differences in storage rate are found, likely owing to climate variability–driven changes in ocean circulation.

Herbivores as drivers of negative density dependence in tropical forest saplings

草食动物是热带森林幼树负密度驱动因素

▲ 作者：Dale L. Forrister、María-José Endara、GordonC. Younkin、Phyllis D. Coley、ThomasA. Kursar，et al

▲ 链接：

http://science.sciencemag.org/content/363/6432/1213

▲ 摘要：

生态学理论预测，热带森林中所观察到的高局部多样性是由密切相关的植物物种内部和之间的负密度依赖相互作用维持的。通过分析共生的Inga同类树木生长和生存的长期数据，研究人员测试了被认为是负密度依赖（NDD）基础的两种机制：资源竞争和食草动物攻击。

研究人员通过调节这些相互作用的关键生态特性以及食草动物群落的相似性，量化了相邻树木的相似性。结果表明，植物化学相似性和植食性群落共享，与幼树生长发育和成活率下降有关，幼树生长和成活率下降也是热带树木生命周期中的一个关键瓶颈。

另外，与资源获取相关的所有性状都不影响植物的性能，这表明相邻树木之间的竞争可能不会影响当地树木的多样性。这些结果表明，草食动物压力是幼树期NDD的主要驱动机制。

▲ Abstract

Ecological theory predicts that the high local diversity observed in tropical forests is maintained by negative density–dependent interactions within and between closely related plant species. By using long-term data on tree growth and survival for coexisting Inga (Fabaceae, Mimosoideae) congeners, we tested two mechanisms thought to underlie negative density dependence (NDD): competition for resources and attack by herbivores. We quantified the similarity of neighbors in terms of key ecological traits that mediate these interactions, as well as the similarity of herbivore communities. We show that phytochemical similarity and shared herbivore communities are associated with decreased growth and survival at the sapling stage, a key bottle neck in the life cycle of tropical trees. None of the traits associated with resource acquisition affect plant performance, indicating that competition between neighbors may not shape local tree diversity. These results suggest that herbivore pressure is the primary mechanism driving NDD at the sapling stage.

遗传学Genetics

Males as somatic investment in a parthenogenetic nematode

雌线虫为了精子而非基因生下雄线虫

▲ 作者：Manon Grosmaire、Caroline Launay、Marion Siegwald、Thibault Brugière，et al

▲ 链接：

http://science.sciencemag.org/content/363/6432/1210

▲ 摘要：

一些线虫会采用假配的生殖模式，假配又被称作依赖精子的孤雌生殖，它是一种无性生殖方式，即雌性会用雄性的精子来激活它们的卵子。然而，精子的DNA是不会被使用的。

研究人员从土壤和腐植质中分离出假配型线虫，以研究其独特的繁殖方法。结果发现，尽管大多数的胚胎是在不用精子DNA的情况下发育并仅生成雌性线虫，但有大约9%的受精会使用雄性的DNA。

当亲代DNA在这些情况中得到混合时，所产生的后代仅为雄性，这可能是因为带有Y染色体的精子能力更强，它们比带有X染色体的精子有更大的穿透卵子的可能性。这些结果意味着雌性线虫会生出雄性，后者的遗传物质不会传播给无性生殖的雌性，但会利用其精子激活它们的卵子。

研究人员表示，所生出的雄性线虫更可能会与它们的同胞姊妹交配，模型显示，它能让这种独特的生殖安排成为一种稳定演化的方法。

▲ Abstract

We report the reproductive strategy of the nematode Mesorhabditis belari. This species produces only 9% males, whose sperm is necessary to fertilize and activate the eggs. However, most ofthe fertilized eggs develop without using the sperm DNA and produce female individuals. Only in 9% of eggs is the male DNA utilized, producing sons. We found that mixing of parental genomes only gives rise to males because the Y-bearing sperm of males are much more competent than the X-bearing sperm for penetrating the eggs. In this previously unrecognized strategy, a sexual females produce few sexual males whose genes never reenter the female pool. Here, production of males is of interest only if sons are more likely to mate with their sisters. Using game theory, we show that in this context, the production of 9% males by M. belari females is an evolutionary stable strategy.

Acoel genome reveals the regulatory landscape of whole-body regeneration

蠕虫基因组揭示了全身再生的调控图景

▲ 作者：Andrew R. Gehrke、Emily Neverett、Yi-Jyun Luo、Alexander Brandt、MansiSrivastava1，et al

▲ 链接：

http://science.sciencemag.org/content/363/6432/eaau6173

▲ 摘要：

全身再生伴随着复杂的转录组改变，然而调解这种动态反应的染色质调控图景仍未被探索。

为了破译编排再生的调控逻辑，研究人员对蠕虫的基因组进行了测序。表观基因组分析显示了数千个再生响应的染色质区域，并确定了动态结合转录因子基序，其中早期生长响应（EGR）结合位点是该蠕虫再生过程中最易改变的。

结合EGR抑制和染色质谱分析表明，EGR是直接调控早期创伤诱导基因的先导因子。通过这种方法推断出的遗传联系使得构建一个全身再生基因调控网络成为可能，从而使基于基因组的跨物种再生比较成为可能。

▲ Abstract

Whole-body regeneration is accompanied by complex transcriptomic changes, yet the chromatin regulatory landscapes that mediate this dynamic response remain unexplored. To decipher the regulatory logic that orchestrates regeneration, we sequenced the genome of the acoel worm Hofstenia miamia, a highly regenerative member of the sister lineage of other bilaterians. Epigenomic profiling revealed thousands of regeneration-responsive chromatin regions and identified dynamically bound transcription factor motifs, with the early growth response (EGR) binding site as the most variably accessible during Hofstenia regeneration. Combining egr inhibition with chromat in profiling suggests that Egr functions as a pioneer factor to directly regulate early wound-induced genes. The genetic connections inferred by this approach allowed the construction of a gene regulatory network for whole-body regeneration, enabling genomics-based comparisons of regeneration across species.