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Science:世界上有四种长颈鹿存在

标签:长颈鹿 物种
摘要 : Gerald不会跳舞;Abigail不会数数;Geoffrey总是笨手笨脚。如今,这些故事书中身材高挑的长颈鹿——拥有长长的脖子、腿、眼睫毛以及能够卷起的紫色舌头,不得不同时担心它们到底属于哪个物种。

 

Gerald不会跳舞;Abigail不会数数;Geoffrey总是笨手笨脚。如今,这些故事书中身材高挑的长颈鹿——拥有长长的脖子、腿、眼睫毛以及能够卷起的紫色舌头,不得不同时担心它们到底属于哪个物种。

对非洲长颈鹿遗传特征进行的更深入研究表明,长颈鹿实际上代表了4个不同的物种。据估测,共有9万只长颈鹿在热带草原的树梢间觅食。因此,大多数环保人士并未过于担心这种有着超凡魅力的动物。不过,如果这个新的“家谱”站得住脚,其中一个长颈鹿物种的数量将少于5000只,从而使其成为全球更多濒临灭绝的哺乳动物之一。

来自纳米比亚长颈鹿保护基金会的研究人员在收集了非洲190只长颈鹿的皮肤样本后,提出了这一新分类。他们让德国研究人员分析了这些样本中的DNA。考虑到长颈鹿的流动性很强,人们期待会发现很多异种交配现象。因此,研究人员对这些DNA是多么的不同感到吃惊—— 一些遗传差异甚至比属于两个单独物种的灰熊和北极熊之间的差异还要大。

为此,研究人员在日前出版的《当代生物学》杂志网络版上报告称,基于长颈鹿的遗传差异,非洲大陆的9个亚种实际上分为4个真正的物种。它们是在125万~200万年前分开的,并且可能仍进行着异种交配,但形成了这4个遗传学上大不相同的种类。

新的分类将这些动物分成南方长颈鹿、马赛长颈鹿、网纹长颈鹿和北方长颈鹿。南方长颈鹿有4万多只,而北方长颈鹿不到5000只。研究人员表示,考虑到过去30年间整个长颈鹿种群从15万只降至约9万只,北方长颈鹿在不久的将来可能会陷入困境。

原文链接:

Surprise! There are four species of giraffe, not one

原文摘要:

Gerald couldn't dance; Abigail couldn't count; and Geoffrey was a klutz. Now, these gangly storybook giraffes, with their long necks, legs, eyelashes, and prehensile purple tongues, have to worry too about what species they are. A closer look at the genetics of Africa's giraffes suggests that Giraffa camelopardalis really represents four distinct species. With an estimated 90,000 browsing the savanna treetops, this charismatic animal is one that most conservationists have not been too worried about. But, if this new family tree holds up, one species numbers fewer than 5000 individuals, making it one of the world's more endangered mammals. The new classification came about after researchers from the Giraffe Conservation Foundation in Namibia collected skin samples from 190 giraffes throughout Africa. They asked researchers in Germany to analyze the DNA in these samples. Given how mobile giraffes are, one would expect a lot of interbreeding, so the researchers were surprised by how different the DNA could be—some genetic differences greater than those between a grizzly and a polar bear, which are separate species. Thus, the team reports online today in Current Biology that, based on their genetic differences, the continent's nine subspecies really break down into four true species that separated between 1.25 million and 2 million years ago. They may still interbreed, but group in these four genetically distinct categories. The new categorization divides these animals into the southern giraffe (G. giraffa), the Masai giraffe (G. tippelskirchi), the reticulated giraffe (G. reticulata), and the northern giraffe (G. camelopardalis). There are more than 40,000 southern giraffes, but fewer than 5000 northern giraffes, and given that the total giraffe population has dropped from 150,000 to about 90,000 in the past 30 years, northern giraffes could be in trouble in the near future, the researchers say.

来源: Science 浏览次数:0

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