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智商可预测,未来试管婴儿将可选择“最聪明的”胚胎
文章来源:http://www.shanghaidaiy.cn  发表时间:2023-06-01
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草莓苗的繁殖方式有匍匐茎繁殖、母株分株繁殖、微繁殖、种子繁殖等方式。前3种属于无性繁殖,后代能与亲代保持完全的致性;种子繁殖属于有性繁殖,后代变异程度很大,跟亲本有很大的区别,所以生产上不会利用种子进行秧苗繁殖。

一、匍匐茎繁殖

匍匐茎是草莓的主要繁殖器官,发生匍匐茎的植株叫母株,母株是匍匐茎营养生长的第一个营养供给源,发生匍匐茎的多少与母株的健壮充实程度直接相关。从母株上发生的匍匐茎本来与花序是同源,二者能根据栽培环境条件的变化而相互转化。一般来说,花芽分化和匍匐茎的发生均以日照12h为界,气温以20℃为界,高温发生匍匐茎,低温引起花芽分化。

但是,经过低温时间的长短对匍匐茎的发生数量能起决定性作用,如促成栽培,植株未经过低温处理就覆盖大棚薄膜的匍匐茎发生数量少;露地栽培经过低温时间长,发生匍匐茎的数量就多。绝大多数的草莓品种都有发生匍匐茎的能力,发生匍匐茎的多少与品种特性、母株定植时期、栽培管理条件以及环境条件等因素有关。

利用匍匐茎繁殖秧苗是草莓生产上普遍采用的繁殖方法,方法简单,管理方便,既可利用生产田直接采苗,又可建立专门的育苗圃。但一般应采用专门的育苗圃进行育苗,在专门育苗圃内,每亩一年内可繁殖3万株壮苗。这种方法繁育的秧苗生命力强,生长旺盛,进入结果期早,当年秋天定植,第二年就能开花结果。新形成的匍匐茎苗还可抽生匍匐茎,通常一个母株能发生5~15个匍匐茎,每个匍匐茎可生长3~5个幼苗。这些匍匐茎苗以发生早的、距离母株近的生长旺,质量好,不易染病。

二、母株分株繁殖

母株分株繁殖又称根茎繁殖或分墩繁殖。这种方法适用于两种情况:一是需要更新换地的草莓园,将所有植株全部挖出来,分株后栽植;二是用于某些不易发生匍匐茎的草莓品种。采用母株分株繁殖时,应在果实采收后,及时加强对母株的管理,适时地进行施肥、浇水、除草、松土等工作,促使新茎腋芽发出新茎分枝。

当母株的地上部有一定新叶抽出,地下根系有新根生长时,将母株挖出,剪掉下部黑色的不定根和衰老的根状茎,选择上部1~2年生根状茎逐个分离,这些根状茎上具有5~8片健壮叶片,下部应有4-5条长4cm以上的米黄色、生长旺盛的不定根,分离出的根状茎可直接栽植到生产园中,定植后要及时浇水,加强管理,促进生长,第二年就能正常结果。这种分株的繁殖方法繁殖系数较低,一般3年生的母株,每株只能分出8-14株适宜定植标准的营养苗。这种分株的新茎苗,多带有分离伤口,容易受土传病菌侵染而感病。

但分株繁殖法不需要专门的繁殖田,不需要摘除多余的匍匐茎和在匍匐茎节上压土等工作,可节省劳力和成本。在分株繁殖时,对只有叶片没有须根的根状茎营养苗,可保留1-2片叶,其余叶片全部剪掉,然后进行遮阴扦插育苗,经过精细管理,使其发根长叶后在秋季定植,越冬前能培育成较充实的营养苗。

三、微繁殖

利用微繁殖育苗,近年来在国际上发展很快,我国也已经开始采用。微繁殖是通过组织培养的手段进行繁殖。草莓微繁殖时将草莓茎尖(约0.5mm)接种在培养基上,诱导出幼芽,在试管中通过腋芽萌发增殖,试管苗经过驯化后移栽到育苗圃中。微繁殖最大的优点是可以获得脱毒种苗,其后代生长势旺盛,整齐一致,果实品质优良,增产效果明显。

四、种子繁殖

太原供卵试管代孕

用种子繁殖的草莓苗,由于成苗率低和性状分离,不能保持原品种的优良特性,所以生产上不采用。但为了杂交育种及选育新品种,为了从远距离引种,为了对某些难于获得营养苗的品种进行遗传基因保留,需要进行种子繁殖。种子繁殖的草莓苗生长旺盛,根系发达,不容易衰老,对不良环境条件适应能力强。一般实生苗经过10~16个月就开始结果。种子繁殖应从优良单株上选择充分成熟的果实,然后将种子取下,摊开晾干,最后将晾干的种子装入袋内保存。

剥取少量草莓种子,可用镊子、小刀或牙签将种子取下,平铺在纸上阴干;或用刀片削下带种子的果皮,平铺在纸上阴干,然后将种子取下,也可将带种子的果皮放入水中,清洗浆液后捞出种子晾干;或者把整个果实包在纱布内揉搓,挤出果汁后再用水清洗,滤出种子,摊开晾干,最后将晾干的种子除去杂质,装入袋内保存。但上述方法比较费工,最简单、安全、快速的取种方法是采用工具法脱粒,就是用高速组织捣碎机或打浆机分离种子,迅速把草莓种子脱粒。

把选好的果实除去果柄,在水中冲洗干净,按果实与水1:1的重量混合,倒入高速组织捣碎机或打浆机的杯中,用慢速搅拌20,静止3-5min后可使种子与捣碎液分离,为了加速捣碎液澄清,可在搅拌前加2%的食盐。采用这种方法脱粒,每千克鲜草莓可获得102-112g种子,脱净率在95%左右,种子不损坏,对发芽无影响,较人工脱粒工作效率可提高8倍以上。在室温条件下草莓种子的发芽力可保持2~3年。草莓种子没有明显的休眠期,可随时播种,一般春播或秋播较好。

为了提高种子的出苗率,播前将种子包在纱布袋内用水浸泡24h,然后放在冰箱内,经0-3℃低温处理15-20天进行播种,发芽率可达70%以上。如果播前对种子进行层积处理1-2个月,也能提高发芽率和整齐度。也可在播种前将种子浸泡12h,种子膨胀后播种效果也不错。在播前不加任何处理的也能出苗,但出苗较晚,出苗率较低且出苗不整齐。草莓种子粒小,适宜播在育苗盆或育苗盘内,盆内装入肥沃、疏松并经过筛的细营养土,如在苗床播种,土壤要平整好,多施腐熟厩肥。播种前先浇透水,水渗后在土面上均匀撒播,然后覆盖0.2~0.3cm厚的细土。

为保持表层土壤湿润,在播种盆上可蒙上塑料薄膜,这样还能增加土温,提早出苗。在20~25℃条件下,播种后15天即可出苗,幼苗生长2~3个月,长出1~2片真叶时进行分苗。可将幼苗栽入装有营养土的小盆或育苗钵中,也可栽入纸袋营养钵,每盆栽一株,摆入育苗床进行精心培育,待苗长到4~5片复叶时,即可带土移栽到大田或育苗圃内,进行进一步培育。一般春播的秋季即可大田定植,秋播的要在第二年春季才能定植,因为幼苗弱小,越冬能力差,冬前定植不易越冬。

如果有一天,你可以选择生育一个小“爱因斯坦”,也可以生育一个智商普通的孩子,你会做出什么样的选择?据科学家预计,未来10年内,人类将可以使用试管婴儿技术选择“最聪明”的胚胎。

Genetics research, conceptual artwork. CHINA DAILY

Couples undergoing IVF treatment could be given the option to pick the “smartest” embryo within the next 10 years, a leading US scientist has predicted.

据美国一名权威科学家预计,未来10年之内,做试管婴儿的夫妇将能够选择“最聪明”的胚胎。

IVF:in vitro fertilization 体外受精联合胚胎移植技术,又称“试管婴儿”

Stephen Hsu, senior vice president for research at Michigan State University, said scientific advances mean it will soon be feasible to reliably rank embryos according to potential IQ, posing profound ethical questions for society about whether or not the technology should be adopted.

美国密歇根州立大学主管科研的副校长徐道辉(斯蒂芬·徐)说,科学进步意味着人类不久就能够对胚胎的潜在智商给出可靠的评分,这项技术是否应该使用将是一个深刻的社会伦理问题。

Hsu’s company, Genomic Prediction, already offers a test aimed at screening out embryos with abnormally low IQ to couples being treated at fertility clinics in the US.

徐道辉的基因组预测公司已经为在美国不孕不育诊所接受治疗的夫妇提供了一项检测服务,旨在筛查出智商异常低的胚胎。

“Accurate IQ predictors will be possible, if not the next five years, the next 10 years certainly,” Hsu told the Guardian. “I predict certain countries will adopt them.”

徐道辉对《卫报》记者说:“准确的智商预测是可能的,即使不是未来5年内,那么在未来10年内也肯定可以。我预计一些国家会采纳这项技术。”

The prospect of a new generation of genetically selected babies has prompted concerns about unintended medical consequences and the potential for deepening existing social inequalities. The science underpinning the claim that intelligence can be meaningfully predicted by genetic tests is also contentious.

新一代基因选择婴儿的前景引发了人们对于意外医疗后果和现有社会不平等可能加剧的担忧。基因检测能够有效预测智商的科学技术也引发了争议。

contentious [kn'tens]:adj.有异议的,引起争论的

Peter Donnelly, a professor of statistical science at the University of Oxford, said any such IQ predictions should be treated with “huge caution”, adding: “I have grave misgivings about it on ethical grounds. I think it’s a really bad idea.”

牛津大学统计学教授彼得·唐纳利说,应该“十分谨慎”地对待此类智商预测。他说:“出于伦理原因,我对此非常担忧。我认为这是一个非常糟糕的想法。”

Since the 1990s, couples undergoing IVF have been able to screen their embryos for mutations in single genes that cause serious diseases such as cystic fibrosis, as well as conditions like Down’s syndrome, caused by chromosome abnormalities.

自上世纪90年代以来,接受试管受精的夫妇已经能够对他们的胚胎进行筛选,以发现单个基因的突变,这些突变会导致严重的疾病,比如囊性纤维化,以及染色体异常导致的唐氏综合征等。

chromosome ['krmsm]:n.染色体

Many other traits, including height, physical appearance, intelligence and disease susceptibility, are known to be partly heritable. But because the genetic component is spread thinly over hundreds or even thousands of DNA regions, it has previously been impossible to screen for these traits.

许多其他特征,包括身高、外貌、智力和疾病易感性,都被认为是部分遗传的。但由于遗传组分稀疏地分散在数百甚至数千个DNA区域,以前不可能对这些特征进行筛选。

In the past decade, as vast genetic databases have been established, this picture has changed. Through analyzing many genes, each making a tiny contribution, it has been possible to calculate what are called polygenic risk scores, which give a person’s likelihood of getting a particular disease or having a certain trait.

在过去的十年里,随着大量基因数据库的建立,这种情况已经发生了改变。通过分析大量基因,每个基因都做出了微小的贡献,就有可能计算出所谓的多基因风险评分,即一个人患某种特定疾病或具有某种特征的可能性。

polygenic[,pli'denik]:adj.多基因的

Genomic Prediction is the first company to take embryo screening into this grey area of risk forecasting, offering to alert couples if an embryo has an “outlier” score for risk of cancers, diabetes, heart disease, dwarfism or low IQ.

基因组预测公司是第一家将胚胎筛查纳入风险预测这一灰色地带的公司。如果胚胎在癌症、糖尿病、心脏病、侏儒症或智商低下等风险方面的评分“异常”,它就会提醒做筛查的夫妇。

outlier ['atla]:n.(统计)异常值

Medical staff put clothes on the newborn test-tube baby at a hospital in Xi'an, Northwest China's Shaanxi province. [Photo/Xinhua]

Prediction for IQ is not good enough to give a reliable ranking, but Hsu said that knowing an embryo has a low score could still be desirable.

智商预测目前还不足以给出可靠的评分,但徐道辉表示,如果一个胚胎的智商评分较低,人们可能还是很想知道。

“Maybe the bottom 1% embryo will grow up to be a great person … even be a scientist, but the odds are against it,” he said. “I honestly feel if we can calculate that score and find a real negative outlier there’s an ethical responsibility for us to report that.”

徐道辉说:“也许评分最低的1%的胚胎长大后会成为一个优秀的人……甚至成为一名科学家,但这种可能性很小。我真的觉得,如果我们能计算出这个评分,发现它低得十分异常,那么我们就有道德责任予以告知。”

The company projects that once high-quality genetic and academic achievement data from a million individuals becomes available, expected to be within five to 10 years, it will be able to predict IQ to within about 10 points.

太原找人帮我代孕

该公司预计,在5至10年内,一旦100万人的高质量基因和学术成就数据可用,它将能够预测智商,误差在10分以内。

Hsu is reticent about whether screening for high intelligence would be ethically justified, saying: “Let me just decline to answer that at the moment.”

徐道辉不愿评论高智商筛查是否符合伦理标准,说“目前我拒绝回答这个问题”。

reticent ['rets()nt]:adj.沉默的;有保留的

In some countries, such as Singapore, there is likely to be a high level of public acceptance and demand for such tests, he suggested. “I think the overwhelming majority would say yes, absolutely, parents should be allowed to do that,” he said. “Before you write your piece, you might just want to think that a billion people on the other side of the world might have a different view.”

智商可预测,未来试管婴儿将可选择“最聪明的”胚胎

徐道辉说,在一些国家,比如新加坡,公众对此类检测的接受度和需求可能会很高。他说:“我认为绝大多数人肯定会赞成允许父母这样做。在你写这篇报道之前,也许应该想想地球另外一端的10亿人可能有不同的看法。”

Whether such tests will become available in the UK would depend on approval from the Human Fertilization and Embryology Authority (HFEA).

这种检测方法能否在英国实施将取决于英国人工授精与胚胎学管理局的批准。

“If the HFEA decides that it’s not right for the UK, I will respect that,” Hsu said, but predicted that “rich people from the UK will fly to Singapore” if they are unable to get the tests locally.

他说:“如果英国人工授精与胚胎学管理局认为这对英国不合适,我会尊重这个决定。”但他预测,如果英国富人无法在当地进行这项检测,“他们会飞到新加坡去做的。”

太原如何找代孕中介

Some in the UK take the view that prospective parents have a right to access such tests. “I don’t think people should be deprived of that knowledge,” said Prof Simon Fishel, the founder of Care Fertility.

在英国,一些人认为未来的父母有权进行此类检测。生育关怀组织的创始人西蒙费舍尔教授说:“我认为不应该剥夺人们的这种知情权。”

Fishel questioned whether there is any ethical difference between picking an embryo ranked highest for IQ or sending a child to a private school. “What’s wrong with ranking an embryo if you can rank a child?” he said. “I think there are plenty of people who’d choose embryo Oxford [rather] than embryo A-level failure.”

费舍尔质疑挑选智商最高的胚胎和送孩子去私立学校之间是否存在伦理上的差异。“如果你能给孩子评分,那给胚胎评分又有什么错呢?”他说。“我认为有很多人会选择未来能考取牛津的胚胎而不是无法通过英国中学高级水平考试的胚胎。”

In practice, though, couples often have only a few embryos to choose from. And there are concerns about unintended consequences. For instance, there is some evidence linking higher polygenic scores for academic ability to higher likelihood of autism.

但实际上,夫妇们通常只有几个胚胎可供选择。此外,人们还担心会出现意想不到的后果。例如,有证据表明,学术能力的多基因得分越高,患自闭症的可能性就越大。

The technology is controversial, but that does not mean it will not gain acceptance in the future, Hsu said, drawing parallels with the reaction to IVF in its early days.

徐道辉说,这项技术存在争议,但这并不意味着它在未来不会被接受,这与早期人们对体外受精的反应类似。

“The IVF pioneers … were called monsters, Frankenstein doctors; it was predicted that these babies would have health problems,” he said. “I am actually reassured by that. IVF is completely normalized now. Everyone who is pointing their finger at [Genomic Prediction] now should go back and read those articles.”

他说:“试管婴儿的先驱被称为怪物,弗兰肯斯坦医生。当时人们预测这些婴儿会有健康问题。实际上,我对此很放心。试管受精现在已经完全正常化。现在,所有指责(基因组预测)的人都应该回去读读那些文章。”

来源:卫报、参考消息网

翻译编辑:yaning

来源:中国日报网

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