科学家发现:一些物种在跨物种交换基因,有草与草之间,甚至有动物与植物之间的。

Recent discoveries of horizontal gene transfer reveal that animals and plants are swapping genes across different species - but how do they do it and what might it mean for evolution?

最近对水平式基因转移的研究发现,动物和植物正在不同物种之间交换基因——但它们是如何做到的,这对进化意味着什么?

Spring in London is almost close enough to taste now, and the camellia, crocus and snowdrop blooms near our New Scientist office have been a testament to the city’s heat island. The first flowers of the year always seem to open a little earlier in central London than in its suburbs due to the higher temperatures of the urban environment. But earlier flowers aren’t just a city phenomenon – a study this month revealed that flowers in the UK are, on average, blooming a month earlier than they were before the mid-1980s due to climate change.

伦敦的春天气息已经快可以闻到了,我们新科学家办公室附近的山茶花、番红花和雪花莲盛开 ,证明这座城市是一座热情的岛屿。由于城市环境的温度较高,一年中的第一朵鲜花似乎总是在伦敦市中心比在其郊区开得早一点。但早期的花朵不仅仅是一种城市现象——本月的一项研究表明, 由于气候变化,英国的花朵平均比 1980 年代中期之前开花提前一个月。

In this month’s newsletter, I’ll be taking a look at organisms that swap genes and what it means for evolution, plus a moth rediscovered in the Andes, a new finding concerning panda breeding, and how birds migrate.

在本月的时事通讯中,我将研究生物交换基因的情况及其对进化的意义,以及在安第斯山脉重新发现的飞蛾、有关熊猫繁殖的新发现以及鸟类如何迁徙等。


New genes and where to get them

新基因以及从哪里获得它们

Now, here’s something surprising. Computational analysis suggests that a species of whitefly (Bemisia tabaci, pictured above) has acquired 50 genes from the plants they eat. No discovery like this has ever been made before, and while we don’t know how the genes got into the flies, there are signs that the genes are functional.

现在,这里有一些令人惊讶的事情。计算分析表明,一种粉虱(烟粉虱,如上图所示) 从它们所吃的植物中获得了 50 个基因。以前从未有过这样的发现,虽然我们不知道这些基因是如何进入果蝇的,但有迹象表明这些基因是有功能的。

This particular story begins in March 2021, when a team published work revealing the first known case of a gene moving from plants into animals, in this same species of whitefly. The gene in question allows plants to store defensive toxins in a safe way, and the fly appears to use it to eat plants without being harmed by these toxins.

这个特殊的故事开始于2021年3月,当时一个团队发表了一项工作成果,揭示了第一个已知 的基因从植物转移到动物的案例,在同一种粉虱中。有问题的基因允许植物以安全的方式储存防御性毒素,而苍蝇似乎用它来吃植物而不会受到这些毒素的伤害。

The finding suggested that horizontal gene transfer – the movement of useful DNA codes between entirely different species – may be much more widespread in the natural world than we suspected. Now, a different team has analysed the DNA of the whitefly to identify a full 50 genes that appear to have come from plants, and experiments suggest that many of them are used by the fly.

这一发现表明,水平基因转移(即在完全不同的物种之间移动有用的DNA 代码)在自然界中可能比我们想象的要普遍得多。现在,一个不同的团队分析了粉虱的 DNA,以鉴定出全部50个似乎来自植物的基因,实验表明其中许多基因被苍蝇使用。

The really intriguing bit for me is: how did these DNA sequences move from the fly’s food and into its own genome? We don’t know, but we have some guesses. Perhaps viruses carried the genes into the flies, or perhaps it was transposons, which are regions of DNA that can move around and jump about the genome.

对我来说真正有趣的是:这些 DNA 序列是如何从苍蝇的食物转移到它自己的基因组中的?我们不知道,但我们有一些猜测。也许病毒将基因携带到果蝇中,或者可能是转座子,这是可以在基因组周围移动和跳跃的 DNA 区域。
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The mystery is even deeper for gene-swapping grasses. Last year, researchers looked at 17 species of grass and found that these species had transferred 170 genes between themselves. There was no evidence of hybridisation through reproduction, and these species don’t directly interact in the way that the whitefly and its food plants do. One idea is that wind pollination may somehow be involved.

对于交换基因的草来说,这个谜团更加深奥。去年,研究人员观察了 17 种草,发现这些物种 在它们之间转移了170个基因。没有证据表明通过繁殖进行杂交,并且这些物种不像粉虱及其食用植物那样直接相互作用。一种想法是可能通过风传花粉的某种方式参与了基因交换。

I love anything that turns our understanding of genetics upside down, especially when there are implications for evolution. We’ve long known that bacteria swap genes – they do this mostly by sharing circles of DNA called plasmids with each other, a process that has had a big impact on us because this is how unrelated strains and species give each other antimicrobial resistance genes. The whitefly studies suggest that the species has found a use for at least some of the genes it has acquired from plants.

我喜欢任何能颠覆我们对遗传学的理解的东西,尤其是当它对进化产生影响时。我们早就知道细菌会交换基因——它们主要是通过彼此共享称为质粒的DNA圈来做到这一点的,这一过程对我们产生了重大影响,因为这就是不相关的菌株和物种如何相互赋予抗菌抗性基因的方式。粉虱研究表明,该物种至少发现了一些从植物中获得的基因的用途。

I’ll be interested to see in coming years if we discover that horizontal gene transfer has played far more of a role in the evolution of complex organisms than we thought. One of the crucial steps for evolution is: how can an organism get new genes? While this may appear a simple issue – mutations in our old genes create new ones that may be useful and shaped by natural sextion – it isn’t usually so easy. What if you need all the genes you already have, and can’t afford to change some or give them over to new functions?

我将有兴趣在未来几年看到,我们是否会发现水平基因转移在复杂生物体的进化中发挥的作用比我们想象的要大得多。进化的关键步骤之一是:有机体如何获得新基因?虽然这似乎是一个简单的问题——我们旧基因的突变会产生新的基因,这些新基因可能有用并受自然选择的影响——但通常并不那么容易。如果你需要你已经拥有的所有基因,却无力承受为了新功能而改变或放弃一些已有基因的代价,怎么办?

Decades of research suggest that the accidental duplication of genes – sometimes just of a handful of them, occasionally the entire genome – has historically provided life with additional genetic source material from which to fashion new innovations and adaptations. I wonder if horizontal gene transfer has enabled something similar, perhaps in a less dramatic and more frequent way.

数十年的研究表明,基因的意外复制——有时只是少数几个,有时是整个基因组——在历史上为生命提供了额外的遗传来源材料,可以从中进行新的创新和适应。我想知道水平基因转移是否启用了类似的东西,也许是以一种不那么引人注目和更频繁的方式。


Understanding plants

了解植物

I think one of the biggest barriers to developing an interest in botany comes not from the fact that plants don’t move, behave and charm us like animals do, but because there are so very many of them and it’s difficult at first to really grasp how they all differ from or relate to one another. But with some understanding of the various family groups and their anatomic traits, you can quickly come to get a “feel” for most plants you encounter. If you show me a grass plant, I almost certainly won’t be able to tell you what species it is, but I will have a good idea of how and where it lives, and how it flowers and reproduces.

我认为培养对植物学的兴趣的最大障碍之一,不是植物不像动物那样移动、表现和吸引我们,而是因为它们太多了,一开始很难真正掌握它们如何彼此不同或相互关联。但是,通过对各种族群及其解剖特征的一些了解,您可以很快对您遇到的大多数植物产生“感觉”。如果你给我看一株草植物,我几乎肯定无法告诉你它是什么物种,但我会很好地了解它的生活方式和地点,以及它是如何开花和繁殖的。

There’s one particular distinction that will help you gain insight into almost all the world’s flowering plants: whether a seed germinates with a single or pair of starter leaves, known as cotyledons. A plant’s seed leaves are thrilling indeed – a sign that you’ve successfully coaxed life from a dormant embryo. When I see this first sign of life, I can immediately tell a lot about a plant, starting with whether it is a monocot (one seed leaf) or a eudicot (two).

有一个特别的区别可以帮助您深入了解世界上几乎所有的开花植物:种子是用单片还是一对双生叶(称为子叶)发芽的。植物的种子的叶子确实令人兴奋——这表明它已经成功地从休眠的胚胎中诱导了生命。当我看到生命的第一个迹象时,我可以立即说出关于植物的很多信息,从它是单子叶植物(一个种子叶子)还是真双子叶植物(两个)开始。

The vast majority of the world’s plants are flowering plants, and of these, 97 per cent of species are either a eudicot or monocot. It’s a distinction that has been made since the 17th century, and it goes well beyond a plant’s first leaves. If you look at plants that germinate with a single cotyledon, you are likely to see parallel leaf veins on their subsequent leaves and, should you have an electron microscope to hand, a single pore in their pollen grains. Another clue is that their flowering parts are usually multiples of three – for example, a tulip (pictured above left) has three petals, six stamens (the male parts) and a stigma (female part) with three lobes. Plants with two cotyledons tend to have net-like veins, three pores in their pollen grains, and their flowers are organised on multiples of four or five. An example are primroses (pictured above right), with their five petals. As a botanist, you learn not to be shy about getting close to a plant’s flowers and leaves and giving them a good inspection, counting and describing their anatomy, ideally with the help of a hand lens.

世界上绝大多数植物都是开花植物,其中97%的物种是真双子叶植物或单子叶植物。这是自17世纪以来发现的一个区别,它远远超出了植物的第一片叶子。如果您观察以单个子叶发芽的植物,您可能会在随后的叶子上看到平行的叶脉,如果您手头有电子显微镜,您可能会在花粉粒中看到一个孔。另一个线索是它们的开花部分通常是三的倍数——例如,郁金香(左上图)有三个花瓣、六个雄蕊(雄性部分)和一个带有三个裂片的柱头(雌性部分)。有两个子叶的植物往往有网状脉,花粉粒中有三个孔,它们的花以四或五的倍数排列。一个例子是报春花(右上图),有五个花瓣。作为一名植物学家,你学会了不要害羞地靠近植物的花朵和叶子,并对它们进行良好的检查、计数和描述它们的解剖结构,最好是在手持显微镜的帮助下。

What’s pleasing about the distinction between monocots and eudicots is that it was based on studying plant anatomy, was then thrown up in the air by the genetic revolution of the past century, but has now landed back in roughly the same place as before. The genetic evidence supports these two major groups, but suggests around 3 per cent of species, including magnolias and water lilies, don’t belong in either. These analyses led to a slight name change – originally known as the dicotyledonous plants, the newer eudicot name reflects the slight tweaking of the group that was informed by genetic evidence.

单子叶植物和真双子叶植物之间的区别令人高兴的是,它是基于对植物解剖学的研究,然后被上个世纪的基因革命抛到了空中,但现在又回到了与以前大致相同的地方。遗传证据支持这两个主要群体,但表明大约3%的物种,包括木兰和睡莲,都不属于这两个群体。这些分析导致名称略有变化——最初称为双子叶植物,较新的真双子叶植物名称反映了遗传证据所告知的该组的轻微调整。

We know the most about eudicots, partly because this group contains three-quarters of all flowering plants (while 22 per cent are monocots), but also because the most-studied plant on Earth is Arabidopsis thaliana , a pretty simple eudicot weed that’s easy to grow and study. One challenge is applying the vast insights we’ve gained from eudicots to their monocot cousins. For example, we know a lot about how eudicot leaves develop, but how does that relate to the very different blades of the grasses, a large group within the monocots?

我们对真双子叶植物了解最多,部分原因是该组包含四分之三的开花植物 (而 22%是单子叶植物),还因为地球上研究最多的植物是拟南芥 ,这是一种非常简单的真双子叶植物,很容易种植成长和学习。一个挑战是将我们从真双子叶植物中获得的广泛见解应用到它们的单子叶植物表亲身上。例如,我们对真双子叶植物的叶子是如何发育的了解很多,但这与单子叶植物中的一大群草的非常不同的叶片有何关系?

That’s one question that now seems to have been solved. One hypothesis has been that blades of grass mostly form from the same type of tissue that forms petioles in eudicots (petioles are the stem-like bit at the base of a leaf). This was based on the fact that eudicot petioles have parallel veins, just like the leaves of monocots.

这是一个现在似乎已经解决的问题。一种假设是,草叶主要由形成真双子叶植物叶柄的相同类型的组织形成(叶柄是叶子基部的茎状位)。这是基于这样一个事实,即双子叶植物的叶柄具有平行的叶脉,就像单子叶植物的叶子一样。

But a new study suggests that an alternative, older hypothesis is likely to be the correct one: the blade part of a grass leaf is equivalent to the main leafy bit of eudicot leaves. The team behind the research determined this by combining genetic approaches with computational modelling to uncover how the shape and structure of the leaves of A. thaliana and maize (a monocot) develop. It’s a familiar approach for me, as my doctoral work involved combining genetic approaches with insights from modellers to understand explosive seed dispersal. The researchers liken their finding to an older discovery in animals, when new genetic evidence reinstated the old and discarded idea that the fronts of our bodies are equivalent to the backs of insects, and vice versa.

但 一项新的研究表明,另一种更古老的假设可能是正确的:草叶的叶片部分相当于真双子叶植物的主要叶状部分。该研究背后的团队通过将遗传方法与计算模型相结合来确定这一点,以揭示拟南芥和玉米(一种单子叶植物)叶子的形状和结构是如何发育的。这对我来说是一种熟悉的方法,因为我的博士工作涉及将遗传方法与建模者的见解相结合,以了解爆炸性的种子传播。研究人员将他们的发现比作较早的动物发现,当时新的遗传证据恢复了旧的和被抛弃的观点,即我们身体的正面等同于昆虫的背面,反之亦然。

Another recent monocot breakthrough was finally finding a way to graft these plants. Attaching the shoots of one plant to the roots of another may sound nothing more than a specialist growing technique, but it’s extremely useful for fighting disease in crops that are propagated as clones. Indeed, it may be the breakthrough we need to save both bananas and the agave grown for tequila. These are both monocot plants and, until now, it was thought that their anatomy made them impossible to graft.

最近的另一项单子叶植物突破终于找到了嫁接这些植物的方法。将一种植物的枝条连接到另一种植物的根部听起来不过是一种专业的种植技术,但它对于对抗作为克隆繁殖的作物的疾病非常有用。事实上,这可能是我们需要拯救香蕉和为龙舌兰酒而种植的龙舌兰的突破。这些都是单子叶植物,直到现在,人们认为它们的解剖结构使它们无法嫁接。


This month I learned…
…that artificially inseminated giant pandas are more likely to reject their newborn cubs than those whose offspring are conceived naturally. A study of 202 cubs born at two panda centres in Sichuan province, China, between 1996 and 2018 found that the 63 cubs conceived through artificial insemination were 37.9 per cent more likely to be rejected by their mothers. This may be because when a female panda doesn’t get the chance to inspect the future father of her children, she can’t be assured of his quality, so is less likely to invest her time and energy in his offspring.

这个月我学习到…人工授精的大熊猫比自然受孕的大熊猫更容易排斥新生幼崽。一项对1996年至2018年间在中国四川省两个熊猫中心出生的202只幼崽的研究发现,通过人工授精受孕的63只幼崽被 母亲拒绝的可能性要高出37.9%。这可能是因为当雌性熊猫没有机会检查孩子未来的父亲时,她无法保证他的质量,因此不太可能将时间和精力投入到他的后代身上。

The team behind the study recommends that panda conservation programmes prioritise natural mating. While rejected cubs can be hand-reared by conservation staff, these infants can miss out on social learning, which can lead to abnormal behaviour as adults.

该研究背后的团队建议熊猫保护计划优先考虑自然交配。虽然被拒绝的幼崽可以由保育人员人工抚养,但这些婴儿可能会错过社交学习,这可能导致成年后的异常行为。

…that a species of deep-sea anglerfish can glow in two different ways. Like plenty of deep-sea fish, the Pacific footballfish (Himantolophus sagamius ) can use symbiotic bioluminescent bacteria to light up its dark home. But we now know that it can also do something called biofluorescence – absorbing one wavelength of bioluminescent light, and then reflecting it as a different colour. This is a rare skill in the deep sea and has never been documented in anglerfish before.

……另一个新知识,深海琵琶鱼可以以两种不同的方式发光。像许多深海鱼一样,太平洋足球鱼(Himantolophus sagamius)可以利用共生的生物发光细菌来照亮它黑暗的家园。但我们现在知道,它也可以做一种叫做生物荧光的事情——吸收一种波长的生物发光光,然后将其反射为另一种颜色。这是深海中罕见的技能,以前从未在琵琶鱼身上记录过。


Newly described species of the month
This month’s “new”-to-science species has actually been described before – but not since 1904. French entomologist Paul Dognin caught specimens of this pale and dappled moth (Rheumaptera mochica) on the western slopes of the Andes in southern Peru 118 years ago, and no scientific observations of the species have been recorded since.

本月介绍的新物种。一个“新”科学物种实际上已经被介绍过——不过自1904年以来就没有被再次介绍过。118年前,法国昆虫学家保罗·多宁在秘鲁南部安第斯山脉的西坡上捕获了这种苍白斑驳的飞蛾 ( Rheumaptera mochica ) 的标本,并且从那以后没有记录对该物种的科学观察。

Now, the moth’s larvae have been found growing on a shrub in northern Chile. The larvae were collected and reared on this plant – a native shrub called Senna birostrisvar. arequipensis – enabling the research team to analyse the species’ DNA and inspect the genitalia of the adult moths, both of which give clues to where the species sits in the family tree of its genus.

现在,人们发现这种飞蛾的幼虫生长在智利北部的灌木上。幼虫是在这种植物上收集和饲养的——一种叫做番泻叶-阿雷基彭斯变种的原生灌木 ,这使研究小组能够分析该物种的DNA并检查成年飞蛾的生殖器,这两者都为该物种在其属的家谱中的位置提供了线索。
原创翻译:龙腾网 http://www.ltaaa.cn 转载请注明出处


The rediscovery of the moth is notable not just because it’s the first scientific record of the species in more than a century, but because we now know one of its host plants and that the species can also be found in Chile.

飞蛾的 重新发现 之所以引人注目,不仅因为它是一个多世纪以来对该物种的第一次科学记录,还因为我们现在知道了它的一种寄主植物,而且该物种也可以在智利找到。
原创翻译:龙腾网 http://www.ltaaa.cn 转载请注明出处



Behold Angustopila psammion, the smallest snail ever identified on land. Discovered in cave sediment in Vietnam, its shell is only 0.48 millimetres high and has a volume of just 0.036 cubic millimetres, about a fifth of a typical grain of sand. The snail probably doesn’t live in caves though – the researchers who’ve described it think it is likely to live in limestone crevices or on plant roots.

另一个新物种。看看 Angustopila psammion,这是陆地上发现的最小的蜗牛。在越南的洞穴沉积物中发现,它的外壳只有 0.48 毫米高,体积仅为 0.036 立方毫米,约为典型沙粒的五分之一。不过,蜗牛可能并不生活在洞穴中——描述它的研究人员认为它很可能生活在石灰石裂缝或植物根部。


Archive deep dive
This month, I’ve enjoyed digging into our archive to better understand how migrating birds use Earth’s magnetic field to navigate. As explained in this 2017 feature, there are two main hypotheses. The first is that birds use crystals of magnetite, which have been found in the upper beaks of some species. This mineral is a form of iron oxide, but it has been difficult to show that it helps the birds with magnetoreception – the sensing of magnetic fields.

档案馆深潜。这个月,我很喜欢挖掘我们的档案,以更好地了解候鸟如何利用地球磁场进行导航。正如 2017 年专题中所解释的,有两个主要假设。首先是鸟类使用磁铁矿晶体,在某些物种的上喙中发现了这种晶体。这种矿物质是氧化铁的一种形式,但很难证明它有助于鸟类的磁感应——磁场感应。
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The second hypothesis is that birds use light-sensitive proteins in their eyes called cryptochromes. Magnetic fields may alter the spin of the electrons within cryptochrome proteins, changing their chemical behaviour and superimposing Earth’s magnetic fields on a birds’ vision. Experiments last year showed that a cryptochrome protein can behave in a way that’s influenced by magnetic fields, perhaps making what a bird sees go lighter or darker depending on the strength and direction of the magnetic field. But we still don’t know that birds really do use these proteins for magnetoreception in real life.

第二个假设是鸟类在它们的眼睛中使用称为隐花色素的光敏蛋白质。磁场可能会改变隐花色素蛋白中电子的自旋,改变它们的化学行为并将地球磁场叠加在鸟类的视觉上。 去年的实验 表明,隐花色素蛋白的行为方式会受到磁场的影响,这可能会使鸟类看到的东西变亮或变暗,具体取决于磁场的强度和方向。但我们仍然不知道鸟类在现实生活中是否真的使用这些蛋白质进行磁感受。

But a related question may have been solved this month – what do birds do if a magnetic field changes? We know that Earth’s magnetic field changes over time, so birds need a way to calibrate their navigational systems. Now, a study of the Eurasian reed warbler (Acrocephalus scirpaceus, pictured above) has found that these birds use how much the Earth’s magnetic field slopes from the horizontal to determine when they’ve reached their destination. Compared with other features of the magnetic field, such as its intensity, the incline drifts the least.

但本月可能已经解决了一个相关问题——如果磁场发生变化,鸟类会做什么?我们知道 地球的磁场会随着时间而变化,因此鸟类需要一种方法来校准它们的导航系统。现在,对欧亚芦苇莺(Acrocephalus scirpaceus,如上图)的一项研究发现,这些鸟类利用地球磁场 从水平方向倾斜的程度 来确定它们何时到达目的地。与磁场的其他特征(如强度)相比,倾斜度漂移最小。