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楼主: 癯鹤

金发蓝眼的猩猩

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 楼主| 发表于 2018-3-6 22:22 | 显示全部楼层
40# 癯鹤
想了很久了,还是百思不得其解!今天看到这个帖子《南方人卷发的来源是什么?》,又想谈谈。卷发在北方也不算罕见,当然这里还是直发为主。本人感觉波发或许跟红毛猩猩有点什么基因联系,非洲猩猩没有卷毛的,猩猩有些会有轻度卷毛。不过对于科伊桑人那种极度奇特的颗粒状毛发,感觉可能跟干热气候有关,君不见穿衣服后隐秘部位的毛发基本都是卷曲的么(在身体上还算湿热,相当于红毛猩猩的曲度;假如是干热,那就更卷曲,参考毛发靠近热源自动卷曲)?时间长了,因为卷曲有利于生活,也就适应环境自然进化而成(环境影响物种起源?物竞天择?希望大家寻觅一下,猿猴类有哪些是卷毛的?又是什么适应环境的原因),当然具体形成性状,还是基因做主,不然为何同在干热地带、湿热地带的人,有些种族就是直发;而寒带,有些种族是波发?(说明可能不是在这些地方进化的,而是后来迁徙?)
我更大的疑惑是为什么人类身体光滑露肤,粗长体毛较少,而头发却大部分(似乎科伊桑人不算?)都是可以长得很长。这个问题真是奇怪得很!
有没可能体毛变成汗毛跟人类穿衣有关,也就是原始人类在有衣服之前,都是长着猴子一样的长毛的?穿衣服后,由于虱子等寄生虫还有闷热,这些毛发就渐渐脱落了(这样的话现代智人就不可能在热带进化出来了,因为那里完全可以不穿衣服,现在还有原始民族不穿衣服呢;那样的话,将是入非洲理论,可能脱毛基因显性强势,把非洲原来有毛的旧人种排挤消灭或基因覆盖了)。后来又有了自我驯化导致的基因突变,就光洁了。这可以解释为什么几十万年前原始人类没有衣服可以生活在高纬度。而野人的传说和个别的毛人返祖现象,似乎是一个证明(非常不过硬的证明,因为野人至今没找到)?但是现代智人各种族都是没毛的(个别有稀疏的浓长体毛),可能是人体内刺激长毛也是使得人类比较粗野的睾丸素等激素随着进化减少的结果?君不见,人类越进化越文明越光鲜么?但是某些数万年也没有走出旧石器的部落除了因为生活方式和体貌特征接近晚期智人不如聪明进步的人漂亮外,也没见毛发多一点。还有一些生活在高纬度相对比较寒冷的地方的少数特殊原始民族,其实穿的也还不算多,为什么不返祖长毛?
头发长长也真是一个特别奇怪的问题。似乎自然界并无类似例子,但是人类饲养的一些动物,比如绵羊、长毛兔、牦牛等,还有长尾鸡等鸟类,似乎毛发相对来说像人类的头发一样可以长得很长,是不是趋同进化、驯化动物、自我驯化这些现象的结合呢?这是很有可能的,但是具体是人影响动物,还是动物影响人?还是微生物才是影响这些寄主的因素?真不好说!
头发长长会是脑容量变大的副作用么(保护大脑?比如在高纬度节省能量并维持头部温度很重要)?那么尼安德特人等这些远古人类(他们是否有衣服,若没有,是否有浑身长毛?不过可能性应该不大,因为尼安德特人基因更多的人种,似乎毛发反倒更少)是不是也有一头秀发(若是一头秀发,那么一定也得有打理头发的技艺,不然影响生活呀)?远古岩画或工艺品有他们的形象么(几万年前现代智人的工艺品是有很多表现远古人类发艺的塑像和发饰的)?头发变长的进化史能追溯到什么时候(晚期智人是肯定的了)?自然界毛发能不停增长的动物似乎只有麝牛(远古北极的那些长毛动物是否也有这些性状),若是头发一直增长的基因是在高纬度进化而来(趋同进化,自我驯化,因为人类捕食跟随高纬度长毛巨物,结果相似的微生物和遗传物质影响人类,导致长毛动物长毛的基因转行跳槽插入了控制人类头发增长的基因里了?远古天然转基因?),而且人类在热带是不用穿衣服也可以的(没有进化出长毛的动力),是否可与出非洲理论相对(真正几十万年在热带的进化的人种似乎头发不但卷曲,还可以自行断掉而长不长,比如非洲科伊桑人、俾格米人、亚洲安达曼群岛那些小黑人土著的头发)?
 楼主| 发表于 2018-5-31 22:50 | 显示全部楼层
四十万年既然是一个地质周期,所以不奇怪看到这么篇新闻。考虑到倭黑猩猩和人类的近似性,话说这种从基因检测找出的幽灵古猩猩,是不是可能为某种半人半猿的古猿(比如南方古猿)呢?另外文中也说了跨物种混交不一定产生不育后代(举了灰熊与北极熊的例子),以此类推,咱的所谓亚洲猩猩与非洲猩猩结合产生猿人的设想也不荒谬啊。地质历史中,蕴含了太多进化之迷。宇宙之大,这又是很偶然的事件。所谓进化,并非一定处于必然的路径,却一定得到必然的结果。路径的随机,与客观结果的必然,是生物进化的常态,乃至于微生物植物动物和谐共生纷繁复杂组成地球生物圈。而外星呢?来自猩猩的你,来自星星的它?

Traces of a mystery ghost ape species that lived around 400,000 years ago is found hidden in the genome of bonobos
  • There are no remains of the ape but proof it existed are in the bonobo genome
  • Mystery DNA accounted for 1% of their overall genetic information in bonobos
  • New ape split from the common ancestor of chimps and bonobos 4m years ago
By Phoebe Weston For Mailonline

Published: 13:00 BST, 31 May 2018 | Updated: 13:00 BST, 31 May 2018
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Traces of a mystery ape 'ghost' species that lived around 400,000 years ago in the forests of central Africa have been found.
There are no remains of the ghost ape but proof it existed has been found in the genome of modern-day bonobos.
Researchers know that this mystery species bred with bonobos - whom they lived alongside for millions of years - and its genes persist in the apes of today.
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A mystery ape species that lived around 400,000 years ago in the forests of central Africa has been found. There are no physical remains of the ghost ape but proof it existed has been found in the genome of modern-day bonobos (stock image)

It was previously thought that different species were not able to produce fertile offspring with one another.
However, it seems many species have mated over the years - such as grizzly bears and polar bears - and produced fertile offspring.
Researchers looked at the genomes of common chimps and bonobos and found they had once also interbred,according to the New Scientist.
Martin Kuhlwilm from the Institute of Evolutionary Biology in Barcelona compared the genomes of 59 wild chimpanzees and 10 wild bonobos.



He found unusual bits of DNA from a ghost source accounted for around one per cent of their overall genetic information.



Using this data, Dr Kuhlwilm found that this mystery ape split from the common ancestor of chimps and bonobos between three and four million years ago.
'This means there was once a third species of chimpanzee living in the forests of central Africa', Dr Kuhlwilm said.
Dr Kuhlwilm says they bred between 400,000 to 100,000 years before Homo Sapiens first evolved.

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Martin Kuhlwilm from the Institute of Evolutionary Biology in Barcelona compared the genomes of 59 wild chimpanzees (stock image) and 10 wild bonobos

The fragments make up three per cent of the ghost ape's genome but research still don't know how much information can be obtained from them.
Dr Kuhlwilm said the 'odds are low' for finding new fossils of the species.
Last month researchers revealed the modern-day ancestors of this ghost ape are twice as numerous in West Africa as previously thought.
Prior estimates on gorillas and chimpanzees numbers were based on nest counts taken from isolated areas across the great apes' habitat range, said the report in the journal Science Advances.
The new count uses mathematical modeling to project likely ape numbers in areas where their nests haven't been directly surveyed by people.
However, the apes are still endangered and in dire need of protection, an international team of researchers found.
Spanning 59 sites in five countries surveyed over 11 years, it is the most comprehensive and accurate dataset ever compiled on these apes, said one of the lead authors, Fiona Maisels, conservation scientist for the Wildlife Conservation Society.
The results show that western lowland gorillas in western equatorial Africa number nearly 362,000, up from prior estimates of 150,000-250,000 individuals.
And chimpanzees in the area are expected to number almost 129,000, up from earlier counts of 70,000 to 117,000.



Read more: http://www.dailymail.co.uk/sciencetech/article-5790793/Mystery-ghost-ape-species-lived-400-000-years-ago-found.html#ixzz5H5bkFxiH
Follow us: @MailOnline on Twitter | DailyMail on Facebook
 楼主| 发表于 2018-10-6 11:28 | 显示全部楼层

哈士奇的蓝眼说明,浅色毛发跟蓝色眼睛确实并非一定关联。另外,斑点狗可能关联蓝眼性状。


The secret of Siberian huskies' piercing blue eyes: Researchers discover gene mutation is responsible in groundbreaking dog DNA study
  • Researchers analysed the DNA of 6,070 purebred and mixed-breed dogs
  • Research was the first time the technique has been used on canines
  • Duplication on chromosome 18 'strongly associated' with blue eyes in Huskies
PUBLISHED: 18:41 BST, 5 October 2018 | UPDATED: 19:32 BST, 5 October 2018

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Siberian huskies are among the most prized dogs in the world thanks to their piercing blue eyes.
And it is all down to a gene mutation that gives the iconic sled dog its famous hypnotising stare, according to new research.
It was identified after scientists compared the genomes of more than 6,000 dogs in the first study of its kind.
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The piercing blue eyes are caused by a gene mutation that gives the sled dog its famous hypnotising stare, according to the biggest ever DNA study of dogs.


The much loved breed carries the variant in a section of DNA that carries genetic information known as 'canine' chromosome 18.
A duplication on canine chromosome 18 was 'strongly associated' with blue eyes in Siberian Huskies, said the US team.
The phenomenon is a major mechanism through which new genetic material is generated during molecular evolution.
Biological anthropologist Dr Aaron Sams, of Embark Veterinary, New York, said: 'The biggest surprise for me was this duplication, which primarily explains blue eyes in huskies, can also explain blue eyes in a subset of Australian shepherds that are tri-coloured (non-merle), which was until now unexplained.'
A genomic-wide association study is often used on humans to uncover DNA clues behind certain characteristics or diseases but has never been done on dogs before.
In such an approach, markers in the genomes of many subjects, in this case animals, are scanned to pinpoint the genetic variations of a trait or illness, such as blue eyes.
In recent years, personal DNA testing companies that promise to offer insight into our ancestry and health have exploded in popularity.
Two genetic factors that cause blue eyes in merle and piebald dogs have previously been revealed, which are due to mutations of a protein that can also produce a patchy fur coat.
But this isn't the case for huskies.
Dr Sams and colleagues at the University of Cornell's College of Veterinary Medicine, New York, analysed the DNA of 6,070 purebred and mixed-breed dogs to get to the bottom of the Siberian husky's crystal-like eyes.
Their owners also sent the researchers photos of the dogs and filled out web-based surveys on their pets. Of the total, 156 dogs had solid blue eyes or partially blue eyes.
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Six week old purebred Siberian Husky puppies in snow at Bright Angel Park, Cowichan Station, Canada.Dr Sams and colleagues at the University of Cornell's College of Veterinary Medicine, New York, analysed the DNA of 6,070 purebred and mixed-breed dogs to get to the bottom of the Siberian husky's crystal-like eyes.


By studying the canines, the researchers discovered what is known as a haplotype, or a set of genetic variants that are found on a chromosome.
The duplication of a variant of the homeobox gene, which plays a key role in how the eyes of mammals develop, appeared to be isolated to Siberian huskies and explained why their eyes were blue.
The duplication of the same gene might also explain why some Australian shepherd dogs have blue eyes.
The study, published in the journal PLOS Genetics, was funded by a dog DNA startup company called Embark.
Added Dr Sams: 'There is definitely more work to be done to fully understand eye colour in dogs.
'For example, while dogs that carry a single copy of this mutation typically have completely or partially blue eyes, in rare cases a dog will carry this mutation but not have blue eyes, which means that other genetic or environmental factors are affecting the expression of this trait.
'In the future, this could give dog breeders control over the eye colour of the litters they breed.'
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The study, published in the journal PLOS Genetics, was funded by a dog DNA startup company called Embark.


The study, published in the journal PLOS Genetics, was funded by a US dog DNA startup company called Embark.
Future studies of the functional mechanism may lead to the discovery of a novel pathway by which blue eyes develop in mammals.
The study is the latest to provide insight on the inner workings of our four-legged friends.
Earlier this year, Italian researchers found dogs could understand human emotions based on facial expressions. If a dog detected a human is having a bad day, for example, its heart rate might rise, they said.



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