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主题:【原创】在转基因争论中有关育种学的一些基本概念 -- 瓦斯

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家园 俺已经另开新贴, 专门讨论这个问题。

俺已经另开新贴, 专门讨论这个问题。

http://www.ccthere.com/thread/3209942#C3209942

家园 转基因也可以不引入“第三者”基因的

一个基础基因组来源,一个外源基因来源。就两者而已。

随便你认为哪个算父亲哪个算母亲都好,人家转基因也未必就一定涉及了“不道德”的第三者插足。

所以从这个角度说明不了任何问题。

家园 对方舟子应该一分为二的看

从学术打假这个角度来说,应该肯定他的工作。

至于在中医和转基因的问题上,这其实就是两个暂时无标准答案的问题,因为谁也不能说中医就一定没道理,谁也不能证明转基因就一定没问题,所以方舟子在这两个问题上截然相反的表现无非就是以下两个原因之一或两者兼而有之:

要么他觉得自己就是上帝,什么都知道。

要么他牵扯到屁股和利益问题,跑出来扮演上帝。

家园 人类大约有3万个基因,水稻甚至比人类还多。

人类大约有3万个基因,水稻甚至比人类还多。

作为亲本,也就是父亲或母亲,需要提供整套基因组。

单个外源基因不是一个基因组,做不成亲本。

家园 对啊,所以如何操作才是关键

而不是说是否有第三者的基因。

家园 本楼只是要讲清一些基本概念

有很多争论的双方,都没搞清楚基本概念。

家园 那请你说一下你具体反对啥?

反对农业部门研究转基因?还是反对农业部门把转基因给我们吃?别人不说,美帝一直在研究转基因,“臭名昭著”的孟山都就是旗手,你想不吃到转基因大米,先去把孟山都之流的灭了。你要是能阻止我国研究转基因,你不是英雄!因为假如我们自己研究的,多少总有些底,我们不研究,美帝先把优秀的种子拿出来,必然是传统的种子完败,农民可不会理会你几十年之后的有可能的危害,必然对新种趋之若鹜,然后才真的是把命脉交在对方手里了。这个其实已经发生了,大豆!

反对转基因的言论,其实完全可以套用在杂交水稻等等上面,两者的分别只是过程和手法,其实都是对“大自然”的人为改变,问题是,人类本身就是反自然的存在,要保护自然,维持“原生态”的生活,先灭掉人类吧。

家园 关于8补充一点

在水稻的栽培中,寻找野生稻的目的是获得更多的可供作为改进水稻性状的遗传物质(我不确定是不是这类遗传资源就是所谓“种质资源”)。因为在人类数千年的水稻的选种过程中,有可能把某些本来可以提高产量的基因丢失。而这类基因仍然会在野生稻中存在。所以为了进一步挖掘水稻增产的潜力。就要从这些野生稻的基因组中找东西。

另外,在植物育种中或许辐射育种不是常规方法。在微生物育种中,辐射诱变是很常用的手段。

家园 俺不反对转基因这个技术。

俺不反对转基因这个技术。 对于技术本身, 俺不但不反对, 俺还很喜欢, 很看好。

俺反对的是不考虑风险的使用转基因技术。转基因技术的风险很大。

俺的观点一时半刻也说不清楚。 俺在河里写了个长贴, 还在写, 俺借瓦斯同学的帖子做个广告, 俺的帖子放在这里 http://www.ccthere.com/thread/3209942#C3209942 欢迎指正!

家园 但实际上您反对的作用也不大啊

早上就看到新闻,孟山都大举进军了……

家园 这个关于危害性的5点争议就是瞎扯淡,

(1)BT蛋白对于昆虫细胞的毒性可能并不特异。实验证明,BT蛋白不仅可以溶解昆虫动物的肠道细胞,而且可以溶解非昆虫细胞来源的磷脂双分子层,并且可以与哺乳动物的肠粘膜细胞发生结合。因此,在高浓度的时候,可能会对哺乳动物造成毒性。

人是哺乳动物没有错,可是不要忘了人和哺乳动物的区别。人类实际上是使用蒸煮食物的,经过蒸煮的bt蛋白还会跟肠粘膜发生结合?

人家做的实验恐怕是用大剂量的bt蛋白(高浓度的,实际上在农产品中是绝对不可能出现的)来直接关系老鼠的肠道吧,连消化和吸收都来不及进行的那种量,人要不是变态,绝对不会去这样接触bt蛋白的。

2)BT蛋白在人体中能够蓄积,其长期毒性不能低估。虽然,BT蛋白对于小鼠的LD50为20g/KG,但其蓄积系数大于6.24,长期摄入可造成肝、肾细胞空泡化,肾血管上皮细胞变性,等肝肾功能损害

这个20g/kg的量是个什么概念,你要是按这个量喝酒,就直接送火葬场了,存货的几率绝对不超过1%。 长期毒性是怎么样的,就必须做大范围的试验了。不过介于bt蛋白对小鼠如此安全,甚至高于人类所必须的微量元素和维生素类,应该对人类的安全是很可靠,不需要特别的大范围长期实验了。

3)BT蛋白抑制机体的免疫功能和造血功能。动物实验证明,长期大量摄入BT蛋白,可以造成机体红细胞减少和造血抑制,同时导致白细胞数量减少。动物实验还表明,摄入BT蛋白的小鼠,其脾脏和胸腺等免疫器官出现明显的萎缩,T细胞的增殖能力明显下降。

请注意“长期大量”几个字,作为人类社会的一员,看帖的各位是没有这个机会的,就是想争取都争取不来。也就是搞这方面实验的几个人可能有机会小酌一杯bt蛋白。

4)BT蛋白具有引起自身免疫性疾病的潜在危险。动物实验证实,BT蛋白能激发机体产生特异性的免疫应答,出现抗BT蛋白的抗体。这些抗体可能识别那些积蓄于自体细胞(如肾小球细胞)表面的BT蛋白,导致自身免疫性疾病,如溶血性贫血和肾脏炎症。同时,在体内存在的BT蛋白还可以与这些抗体形成循环的抗原-抗体复合物,导致肾炎或其它自身免疫性疾病(如红斑狼疮和类风湿性关节炎等等)。

任何不是人体本身的东西都有可能引起自身免疫性疾病。这话就等于没说,海鱼还能引起很大一部分的过敏反应呢,所有的药物,食品,都有可能引起,还不是潜在的,是非常肯定每天都有病例的。所以这话就等于没说,要说潜在的话,说明还是比一般食物更安全了。

5)BT蛋白可以引起超敏反应。研究证明,BT蛋白可以引起机体产生IgE型的特异性抗体,从而引发I型超敏反应,导致荨麻疹和哮喘发作等等。

引起超敏反应的东西太多了,青草,猫,够,尘螨,所有化妆品,花粉都可以。这个个体的过敏体质有关,和过敏原其实没有什么关系。等将来基因工程成熟了,能够运用于人体的时候,或许倒能彻底解决这个过敏问题了。

引用这样的东西来证明自己的观点,几乎可以说是在采用反证法。

要是被文章的作者看到,估计他要哭了。

家园 岂止是害虫们觉得人类邪恶

养鸡场的鸡和养猪场里的猪也觉得人很邪恶的,人家可是会哭会叫会流泪的哦。那这些哺乳动物煽情效果可好多了。

生物界就只有对立的两方吗?还是此消彼长的两方,您真有想象力。作为这一方的一员,还在这里替另一方着急,境界不是一般的高。不过我看着怎么都是杞人忧天啊。

你怎么就能确定这种变化会对生态平衡和整个生物链造成非常可怕的,不可预期的影响呢,还把这种影响列为关键点。你能说说怎么造成你说的这个后果,把转基因和这种后果联系起来的例子你能举一个吗?别用这还用说吗这种,我被这样的话骗多了,属于不见棺材不掉泪的那种人。

你怎么就能肯定,敌敌畏,六六六这些东西在仍然大范围使用的情况下,在100年内其影响会逐渐减少呢。你能不能把减少的途径说来听听呢。因为据我所知,这些东西是有蓄积性的,土壤中会越来越多,最后造成灾难。

你大可回答了我提的问题再担心不迟。

家园 请注意,还不能吃熟的,必须生吃。

假设这个米不太正常,搞了一半的bt蛋白,那也要吃4斤啊。吃熟的也够我吃一个星期的了,吃生的我估计一年都吃不完了。

家园 您其实没有看懂这5点危害究竟危害在哪里。

您其实没有看懂这5点危害究竟危害在哪里, 或者说,您其实没有看懂这5点危害究竟是在说什么。

1。 (1)BT蛋白对于昆虫细胞的毒性可能并不特异。实验证明,BT蛋白不仅可以溶解昆虫动物的肠道细胞,而且可以溶解非昆虫细胞来源的磷脂双分子层,并且可以与哺乳动物的肠粘膜细胞发生结合。因此,在高浓度的时候,可能会对哺乳动物造成毒性。

上面这句话是说, 1。 我们种植的BT转基因大豆, BT转基因土豆, BT转基因大米, 这些需要 “长期大量” 食用的东西, 如果BT蛋白对昆虫细胞的毒性不特异的话, 呵呵, 那就好玩了。

比如, 你吃了炒土豆丝, 但是, 饭店里的厨师为了追求口感,炒得嫩一些, 脆一些, 也就是说, 炒得生一些, 呵呵, 您这位“食用蒸煮食物的人类”就很可能摄入有生物活性的BT毒蛋白, 而不仅仅是变性后的蛋白。 如果有人特别喜欢炒土豆丝, 也特别喜欢炒得嫩一些, 脆一些, 这种人可能很多,特别是北方的一些省份, 比如陕西, 山西, 东北什么的, 呵呵, 那么, 这些“食用蒸煮食物的人类” 可能比偶尔吃一次土豆丝的您更加倒霉。

再比如大豆, 经常用来榨油, BT毒蛋白是否会在豆油内存留, 是否有人那它做色拉油, 生吃, 呵呵。 西方人和中国人在食用习惯的一个非常大的不同就是:他们太喜欢生吃食物了! 几乎所有的蔬菜, 他们都可能生吃!

又比如, 转基因土豆, 或者大豆, 农民拿它来喂家畜, 家禽什么的, 如果BT毒蛋白对昆虫不特异的话, 呵呵, 因为他们不是“食用蒸煮食物的人类”, 所以, 他们要倒大霉了, 因为, 他们是“长期大量”食用这东西。

再比如, 很多鸟类, 他们可能会吃下吃了BT毒蛋白的昆虫的幼虫, 那么,由于他们也不是“食用蒸煮食物的人类”, 他们也随着食用昆虫摄入了BT毒蛋白! 呵呵。至于我们究竟威胁到了多少种鸟类的生存, 我们这些“食用蒸煮食物的人类”是不会关心的。 好玩吧。 呵呵。

另外, BT毒蛋白是否那么容易变性, 俺也不知道, 毕竟, 俺知道, 疯牛病的所谓的病毒, 也就是那个毒蛋白, 是很难高温杀灭的, 据说要用高温高压强碱才能杀死(如摄氏134度下加热1小时,才能杀死表面疯牛病毒),不知我们这些“食用蒸煮食物的人类”, 有几个人会这样做饭的。呵呵

-------------------------

2)BT蛋白在人体中能够蓄积,其长期毒性不能低估。虽然,BT蛋白对于小鼠的LD50为20g/KG,但其蓄积系数大于6.24,长期摄入可造成肝、肾细胞空泡化,肾血管上皮细胞变性,等肝肾功能损害

上面这句话是说呢, 俺要解释几个名词1. LD50, LD50是所谓的半数致死量, 也就是说, 让一个叫小明的小鼠和小明的哥哥大明吃下20g/KG的BT毒蛋白, 小明或者小明的哥哥大明两个老鼠之中必有一个会被毒死! 这叫半数致死量。[/COLOR] , 各位看官, 俺们现在讨论的不是某种药物, 而是要讨论诸如土豆, 玉米, 水稻, 大豆子类的,我们要“长期大量”食用的主食!

[COLOR=blue]蓄积系数是指多次染毒使半数动物出现毒性效应的总有效剂量(ED50(n))与一次染毒的半数有效量的比值。

也就是说,讨论的是如果你不会一次吃下这么多的BT毒蛋白, 那么, 不要紧, 慢慢吃, 因为BT毒蛋白有积蓄性! 呵呵。长期摄入可造成肝、肾细胞空泡化,肾血管上皮细胞变性,等肝肾功能损害, 所以,不要着急, 慢慢吃, 就可以看到很有趣的结果。

比如这样:食用转基因土豆老鼠肠胃中出现异常增生细胞(它不是直接吃BT毒蛋白,而是像人一样, 吃土豆)

[IMGA]http://mzd.wyzxsx.com/i/?u=http://hiphotos.baidu.com/%B7%E8%BF%F1%B5%C4%C4%C8%CB%FE%E6%AB/pic/item/d8b65654539fde6bd00906fe.jpg[/IMGA]

食用转基因大豆小鼠肝部细胞发生异变

[IMGA]http://mzd.wyzxsx.com/i/?u=http://hiphotos.baidu.com/%B7%E8%BF%F1%B5%C4%C4%C8%CB%FE%E6%AB/pic/item/9e575e6252fcbbeee6113af7.jpg[/IMGA]

食用转基因大豆的雄性小鼠睾丸颜色变深 结构发生改变

[IMGA]http://mzd.wyzxsx.com/i/?u=http://hiphotos.baidu.com/%B7%E8%BF%F1%B5%C4%C4%C8%CB%FE%E6%AB/pic/item/6dab3a35cc5adcb8a71e120e.jpg[/IMGA]

其实这个东西还是在讨论小明和小明哥哥的生死问题, 而不是讨论诸如土豆, 玉米, 水稻, 大豆这些食物本应该的, 用食物填饱肚子的问题。

呵呵。

后面的几点俺就不一一讨论了, 其实, 仔细就可以看得懂, 应该不难懂。

如果您认为还不够, 呵呵, 自己上网查一下吧, 比如这些:

65 Health Risks of GM Foods

Section 1: Evidence of reactions in animals and humans

1.1 GM potatoes damaged rats

1. Rats were fed potatoes engineered to produce their own insecticide.

2. They developed potentially precancerous cell growth in the digestive tract, inhibited development of their brains, livers and testicles, partial atrophy of the liver, enlarged pancreases and intestines and immune system damage.

3. The cause was not the insecticide, but in all likelihood was the process of genetic engineering.

4. GM foods on the market梬hich were created with the same process梙ave not been subject to such an extensive testing protocol.

1.2 Rats fed GM tomatoes got bleeding stomachs, several died

1. Rats were fed the GM FlavrSavr tomato for 28 days.

2. Seven of 20 rats developed stomach lesions (bleeding stomachs); another 7 of 40 died within two weeks and were replaced in the study.

3. The tomato was approved despite unresolved safety questions by FDA scientists.

1.3 Rats fed Bt corn had multiple health problems

1. Rats were fed Monsanto's Mon 863 Bt corn for 90 days.

2. They showed significant changes in their blood cells, livers and kidneys, which might indicate disease.

3. Although experts demanded follow-up, Monsanto used unscientific, contradictory arguments to dismiss concerns.

1.4 Mice fed GM Bt potatoes had intestinal damage

1. Mice were fed either GM potatoes engineered to produce the Bt-toxin or natural potatoes spiked with Bt-toxin.

2. Both diets created abnormal and excessive cell growth in the lower part of their small intestine (ileum).

3. Similar damage to the human small intestine might result in incontinence or flu-like symptoms, and may be precancerous.

4. This study overturns the assumptions that Bt-toxin is destroyed during digestion and is not biologically active in mammals.

1.5 Workers exposed to Bt cotton developed allergies

1. Agricultural laborers in six villages who picked or loaded Bt cotton reported reactions of the skin, eyes and upper respiratory tract.

2. Some laborers required hospitalization.

3. Employees at a cotton gin factory take antihistamines everyday.

4. One doctor treated about 250 cotton laborers

1.6 Sheep died after grazing in Bt cotton fields

1. After the cotton harvest in parts of India, sheep herds grazed continuously on Bt cotton plants.

2. Reports from four villages revealed that about 25% of the sheep died within a week.

3. Post mortem studies suggest a toxic reaction.

1.7 Inhaled Bt corn pollen may have triggered disease in humans

1. In 2003, approximately 100 people living next to a Bt cornfield in the Philippines developed skin, respiratory, intestinal reactions and other symptoms while the corn was shedding pollen.

2. Blood tests of 39 people showed an antibody response to Bt-toxin, which supports梑ut does not prove梐 link.

3. The symptoms reappeared in 2004 in at least four other villages that planted the same corn variety.

4. Villagers also attribute several animal deaths to the corn.

1.8 Farmers report pigs and cows became sterile from GM corn

1. More than 20 farmers in North America report that pigs fed GM corn varieties had low conception rates, false pregnancies or gave birth to bags of water.

2. Both male and female pigs became sterile.

3. Some farmers also report sterility among cows.

1.9 Twelve cows in Germany died mysteriously when fed Bt corn

1. Twelve dairy cows died on a farm in Hesse Germany, after being fed a diet with significant amounts of a single GM corn variety, Bt 176.

2. Other cows in the herd had to be killed due to some mysterious illness.

3. Syngenta, the producers of Bt 176, compensated the farmer for part of his losses, but did not admit responsibility for the cow deaths.

4. In spite of demands by the farmer and even public protests, no detailed autopsy reports were made available.

1.10 Mice fed Roundup Ready soy had liver cell problems

1. The liver cells of mice fed Roundup Ready soybeans showed significant changes.

2. Irregularly shaped nuclei and nucleoli, an increased number of nuclear pores and other changes, all suggest higher metabolism and altered patterns of gene expression.

3. The changes may be in response to a toxin.

4. Most of the effects disappeared when GM soy was removed from the diet.

1.11 Mice fed Roundup Ready soy had problems with the pancreas

1. Mice fed GM soy showed changes in the synthesis and processing of digestive enzymes.

2. The production of alpha-amylase, a major digestive enzyme, dropped by as much as 77%.

3. This, combined with other pancreatic changes, suggests that GM soy may interfere with digestion and assimilation, as well as alter gene expression.

1.12 Mice fed Roundup Ready soy had unexplained changes in testicular cells

1. The structure and gene expression pattern of testicle cells of mice fed Roundup Ready soybeans changed significantly.

2. The cause for the changes is unknown, but the testicles are sensitive indicators of toxins.

3. Some of the changes might possibly influence adult fertility as well as the health of the offspring.

4. Mouse embryos from GM-fed mothers did show a temporary decrease in gene expression.

1.13 Roundup Ready Soy Changed Cell Metabolism in Rabbit Organs

1. Rabbits fed GM soy for about 40 days showed significant differences in the amounts of certain enzymes in their kidneys, hearts and livers.

2. A rise in LDH1 levels in all three organs suggests an increase in cellular metabolism.

3. Changes in other enzymes point to other alterations in the organs.

1.14 Most offspring of rats fed Roundup Ready soy died within three weeks

1. Female rats were fed Roundup Ready soy starting before conception and continuing through pregnancy and weaning.

2. Of the offspring, 55.6% died within three weeks compared to 9% from non-GM soy controls.

3. Some pups from GM-fed mothers were significantly smaller and both mothers and pups were more aggressive.

4. In a separate study, after a lab began feeding rats a commercial diet containing GM soy, offspring mortality reached 55.3%.

5. When offspring from GM-fed rats were mated together, they were unable to conceive.

1.15 Soy allergies skyrocketed in the UK, soon after GM soy was introduced

1. In a single year, 1999, soy allergies in the UK jumped from 10% to 15% of the sampled population.

2. GM soy was imported into the country shortly before 1999.

3. Antibody tests verify that some individuals react differently to GM and non-GM soy varieties.

4. GM soy also has an increased concentration of a known allergen

1.16 Rats fed Roundup Ready canola had heavier livers

1. The livers of rats fed GM canola were 12-16% heavier than those fed non-GM varieties.

2. The liver is a chemical factory and primary detoxifier for the body.

3. Heavier livers may indicate liver disease or inflammation.

4. If this were caused by oil-soluble toxins, they may be present in canola oil.

1.17 Twice the number of chickens died when fed Liberty Link corn

1. The death rate for chickens fed Chardon LL GM corn for 42 days was 7%, compared to 3.5% for controls.

2. GM-fed chickens also had more erratic body weight and food intake, and less weight gain overall.

3. The study was designed so that only huge differences would be statistically significant.

4. The results were therefore dismissed without follow-up.

1.18 GM peas generated an allergic-type inflammatory response in mice

1. In advanced tests not normally part of GM crop evaluations, protein produced by GM peas generated a dangerous immune response in mice.

2. That 搒ame?protein, when produced naturally in beans, had no effect.

3. The GM peas produced a subtle, hard-to-detect difference in the way sugar molecules attached to the protein, which likely caused the problem.

4. The response in mice suggested that the GM peas could provoke inflammatory or allergic reactions in humans; commercialization of the peas was therefore cancelled.

5. This type of subtle but dangerous change in the GM protein would rarely, if ever, be detected in the safety assessments typically used to approve GM crops.

1.19 Eyewitness reports: Animals avoid GMOs

1. When given a choice, several animals avoided eating GM food.

2. In farmer-run tests, cows and pigs repeatedly passed up GM corn.

3. Animals that avoided GM food include cows, pigs, geese, squirrels, elk, deer, raccoons, mice and rats.

1.20 A GM food supplement killed about 100 people and caused 5,000-10,000 to fall sick

1. One brand of the supplement L-tryptophan created a deadly US epidemic in the 1980s

2. The company genetically engineered bacteria to produce the supplement more economically.

3. Their product contained many contaminants, five or six of which were suspected as the cause of the disease.

4. Discovering the epidemic required multiple coincidences, suggesting that adverse reactions to GM foods may be hard to identify.

家园 别的咱先不要扯开去,就说你奉为真理的这篇吧

我看了你下面回复链接里的文章。好像是两位作者的全版吧。

全文的题目是《转bt蛋白基因食品对免疫系统及其功能潜在影响的研究进展》,请注意后半部分,对免疫系统及其功能潜在影响的研究进展。

就这篇论文而言,完全就没有提及半数致死量,20g/kg这样的内容,人家根本就不是讨论这个来的。 这个半数致死量我不知道是你自己加上的还是有别的出处。 话说河里还是比较鄙视夹带私货的,尤其是这种很可能没有来头的私货。希望你能列出其来源。

其实我想告诉你的是,就是这个半数致死量就算是真的,也说明不了任何问题,反而可能说明了bt蛋白对人类是安全可靠的东西。

为什么这么说呢。就以你说的土豆来说吧

土豆主要成分是淀粉,其中蛋白质的含量一般只有1.7%。也就是说100克土豆里总共就只有1.7克是蛋白,姑且认为这1.7克全是bt蛋白了(其实人家要传宗接代,能有10%是bt蛋白就很好了),那么你这个半数致死量要达到多大的土豆摄入量呢,就按摄入者体重50kg的标准来算吧,他需要摄入59kg的土豆才能达到这个剂量。这个剂量是很夸张的,虽然实际上严格计算这个剂量还要大上10倍。

由于你给出的这个半数致死量没有剂型,食用方法,食用时间跨度(这要是没跨度,一小时内吃下去任何人都得死,不过是撑死),所以我也不好具体批评你这个半数致死量实验方法套用到人类的不合理之处。所以还是期望你能明确其来源。

说到在肉食动物体内的蓄积,那也是没有意义的,因为现在没有人茹毛饮血,即使偶尔吃点生鱼片啥的,那个量也离你提出的这个标准远的很。

此外你提到什么夹生土豆丝完全是个笑话,用油炒的话,起始的油温有200度吧,从油锅转一圈,条状的土豆丝有多少部分能始终保持在50度一下,另外炒的土豆丝要加调料加盐吧,这些可是在常温下都会是蛋白质变性的哦。

你不会以为蛋白跟水一样,要100度才会发生变性吧。

就算bt蛋白在人体内会累积,要累积到20g/kg的量,恐怕也是完全不可能。为了达到你说的这个剂量,恐怕人要专吃这些含有大量bt蛋白的食品才行,还是必须要生吃。

关于蛋白质的变性,初级的医学教科书里有明确解释,对可导致蛋白变性的因素一一列出了。这个不难查到。

你说的疯牛病的朊病毒,也就是个假说而已。你不要选择性的过滤掉那些“可能”,“假说”这些字眼。具体的机制如果得到确认,炸药奖应该是有的。

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