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科学美国人60秒:Red Birds Carry On Colorful Chemistry

2016-06-07来源:scientificamerican
The redder, the better. And I’m not talking about beets, roses or presidential candidates. I’m talking birds. Well, some birds. In various species, red coloration in a male’s feathers or beak is an indication of fitness. A splash of red can attract a mate or warn off a rival.
越红越好。我说的可不是甜菜玫瑰花或者美国总统候选人。我说的是鸟儿, 而且只是某些种类的鸟。 在一些鸟中, 雄性的羽毛或者鸟喙的红色代表健康。 一抹红色能吸引到雌性或警告敌人不许靠近。

Now two teams of researchers have determined the chemistry that allows our flamboyantly feathered friends to cloak themselves in crimson. Bottom line: many birds eat plants that are rich in compounds with a distinctive yellow pigmentation—which some birds can modify chemically to form the red pigment that becomes their calling card.
现在有两个研究小组已经研究出,究竟是何种化学物质使得这些艳丽羽毛的小伙伴们可以把自己隐藏在一片火红中。结果就是: 许多鸟类吃的植物中富含一种特别的黄色色素——对某些鸟类而言,它们可以将其进行化学更改从而变成代表它们这类群体的红色色素。

To tease out the details, the scientists compared birds that can make the red compounds with those that can’t.
为了搞清楚细节,科学家们将对可转化色素的鸟类与不可转化色素的鸟类进行了比较研究。

The first team studied the red canary, which was created about a century ago by breeders who crossed the more familiar yellow canary with a bird called a red siskin. The researchers combed through the genomes of all three kinds of birds to see whether red canaries got any reddening genes from the siskin side—genes that their yellow brethren lack.
第一个研究小组研究红色金丝雀。红色金丝雀是一个世纪之前,由饲养人员将黄色金丝雀和一种名为黑头红金翅的雀类进行杂交而得到的品种。 研究人员们从基因组的层面上对这三种相关种类的鸟类进行了彻底调查,旨在了解是否红色金丝雀是从金翅雀遗传了某些可以使自己变红的基因——而这些基因是黄色金丝雀所缺乏的。

Their search pointed them to a member of the cytochrome P450 family. These are enzymes that are often involved in breaking down toxins. The particular enzyme for turning yellow to red was at levels a thousand times higher in the skin of red canaries compared to their yellow fellows.
研究发现细胞色素P450家族中的一位成员。这个家族的酶用于清除有毒物质。他们发现的这种特殊的酶可以使黄色转变为红色,同比黄色的金丝雀类,该酶可以使红色金丝雀皮肤中积累高达一千倍多的红色色素。

The second research team arrived at a similar conclusion based on studies of zebra finches. Most zebra finches have a bright orange-to-red beak. But one kind of mutant zebra finch has a yellow beak.
第二个研究小组根据对斑胸草雀的研究也得出了相似的结论。大部分斑胸草雀都有一个绚丽的橙色到红色变化的鸟喙。但是有一种被认为有突变的斑胸草雀,只有一种黄色的鸟喙。

Turns out that these yellow-beaked birds have multiple mutations in and around their P450 genes. Which pretty much cut the yellow-to-red enzyme levels in their beaks down to zero. The findings can be read in the journal Current Biology.
研究结果显示,这些黄色鸟喙的鸟在P450基因中出现了多种突变显现。结果使得鸟喙中有黄色转变为红色的酶的含量降低甚至为零。该研究结果已经发表在《当代生物学》杂志上。

Interestingly, many birds that are not red still have cytochrome P450genes—to make red pigments in the retina that enhance their color vision. If they could somehow activate this enzyme in other parts of their bodies, they might both see well and look even better. Or maybe just redder.
有趣的是,许多鸟类虽然不是红色的但是仍然含有细胞色素P450基因——可以使它们的视网膜中积累红色色素增强它们对颜色的视觉感应。如果哪天它们身体的其它部分中的这种酶被激活,它们也许外观更突出,视力也更进一步。或者也许就只是颜色变得更红了。