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〈歡迎翻印流通本文，及網路連接；欲做他用，請先連絡作者易象乾博士。
電郵: epstein@sfsu.ed〉
人類基因之應用
當愈來愈多的人類基因被植入非人類生物
，用以創造在基因上來說是部份人類的新生命型態之際，新的道德問題產生了。一個生物必須含有多少百分比的人類基因才能被視為人類？例如，一只青椒〈註38〉必須具足多少個人類基因，人才覺得吃了它會良心不安？對葷食者
而言，可能在吃豬肉時也會面臨同樣的問題。如果人類享有道德上的特殊地位，那麼一個生物體內存在的人類基因，是否會改變它在道德上的地位？如果一個基因工程被改造過的老鼠，被用來生產人類的精子〈註39〉，而其精子繼而被用於受孕懷胎，產下人類嬰孩，那又當如何呢？
數家公司正致力研發包含人類基因的器官的豬隻，以方便將器官移植於人類身上。其基本的概念是：你可以擁有植入了你的基因的私用器官捐贈豬，所以當你的某個器官壞了，你可以用這隻豬的器官替換。
美國食品藥物管理局〈FDA〉於一九九六年九月，發佈了一套異種移植的方針，允許將動物器官移植到人體，並將有關健康與安全的責任，交付地方醫院與醫學評審委員會。為數四十四人的濾過性病原體學者、靈長類研究者、愛滋病專家，指責食品藥物管理局的方針，說道「根據以往對於穿越品種而感染的愛滋病、B型泡疹濾過性病原體、伊伯拉病原體〈Ebola〉，以及其他濾過性病原體等所累積的
知識，將動物用於少數病人身上尚不可行，新的傳染性媒介者一旦蔓延，潛在的代價可能是上百千，乃至百萬條人命。」〈註40 〉
有鑒於此種移植方式過於危險，英國已立法禁止。〈註41 〉
人類基因工程改造的物質可經由食物、細菌或濾過性病原體進入體內。包含基因工程改造的物質、經由天然過程而產生的濾過性病原體，其致命的危險，己如前述。
動用和重組病菌媒介體來生產病原體，確
實有其危險。在法國的裴斯特研究所裡，六位從事致癌基因的基因工程科學家，在十年間相繼罹患癌症。〈註42〉
基因工程改造的非人類基因，也可通過基因工程改造的疫苗及其他藥品，以及使用為防範「排斥外來物」問題，而以基因工程改造的含人類基因的動物器官，從而進入體內。基因治療的應用，在於修正引發某些遺傳性疾病、有缺陷的人類基因，過程涉及將新的基因蓄意引進體內，以期修正身體的基因構造。它所依據的是簡化而謬誤的基因作用模式，假設個別基因與個別作用之間，為一對一的相應關係。由於基因間的橫向互動〈註43〉已被證實，新基
因的介入可能導致無法預期的後果。另一個問題是先前提到的「藍圖基因」的「詭譎趨勢」，
如今我們已經順著這個趨勢，將基因工程改造的生長荷爾蒙，試驗性地注入身高較矮的健康兒童，只因為他們的父母想要他們長高一點。〈註44〉
附註：
38.在中國大陸，「國家蛋白質工程與植
物基因工程實，驗室」，兼北京大學副校長的陳章良﹝譯音﹞教授，主管一個「將人類基音植入番茄與甜椒中，以控制其成熟的實驗室。」〈《中國科技之一大突躍》亞瑟﹒費雪〈ArthurFisher〉著、一九九六年八月的《通俗科學》
特刊：中國的科學與科技，第四十二頁。〉
39.見刊載於一九九八年一月三十一日《 新科學家》的「代用父親」一文。
40.一九九七年一月二十四日《IP/Biodiv
新聞》。有關「生命異種版」〈xenographs〉的進一步的資料，請參考艾力克斯﹒費諾等著、紐約州「醫藥研究現代化委員會」的「豬、靈長類、疫病：動物--人體器官移殖之通俗手冊」，無出版日期。
41.倫敦〈聯合新聞〉英國在星期四禁止
將動物器官移殖到人體，並聲明必須先對疾病傳播的危險做進一步的暸解。政府指派的一組專家先前提出報告，主題是關切動物器官中的濾過性病原體，在移殖後會給人類帶來新的疾病，政府有鑒於此而做出這項決定。......我們已知豬帶有數種「逆轉病毒」......這一科的濾過性病原體包括了HIV--其中的一種還是兩年前才發現的。研究顯示，其中某些會感染實驗室中的動物細胞......不過英國已經表明，如有需要，將會動用緊急令以禁止人體試驗...。
所用的豬隻是以人類基因來培養的，以便為牠們的器官散覆上人類的分子，以防止在移殖到病人身上時，發生嚴重排斥的情形......
。〈一 九九七年一月十六日聯合新聞。〉
42.何〈Ho，譯音〉一九九六年就一九
八七年六月十八日〈新科學家〉第二十九頁中的資訊所做的報告。
43.橫向基因轉移是指「以濾過性病原體
感染的方式，通過片斷的基因物質，亦即脫氧核酸〈DNA〉，經由細胞從環境裡接收，或藉由非常態的無親屬關係品種間的交配，而將基
因轉移到無親屬關係的品種。」〈何梅文﹝MaeWan Ho譯音﹞著〈基因工程：美夢？噩夢？ 〉第十三頁。)
44.同上，第一九一頁。
待續
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(Permission is granted to reproduce this
article, to distribute it without charge, and to provide
links to it. Please contact the author at epstein@sfsu.ed
regarding other uses.)
USE OF HUMAN GENES
As more and more human genes are being inserted into
non-human organisms to create new forms of life that are
genetically partly human, new ethical questions arise. What
percent of human genes does an organism have to contain
before it is considered human? For instance, how many human
genes would a green pepper38 have to contain before one
would have qualms about eating it? For meat-eaters, the same
question could be posed about eating pork. If human beings
have special ethical status, does the presence of human
genes in an organism change its ethical status? What about
a mouse genetically engineered to produce human sperm39 that
is then used in the conception of a human child?
Several companies are working on developing pigs that have
organs containing human genes in order to facilitate the use
of the organs in humans. The basic idea is something like
this. You can have your own personal organ donor pig with
your genes implanted. When one of your organs gives out, you
can use the pig's.
The U.S. Food and Drug Administration
(FDA) issued a set of xenotransplant guidelines in September
of 1996 that allows animal to human transplants, and puts
the responsibility for health and safety at the level of
local hospitals and medical review boards. A group of 44 top
virologists, primate researchers, and AIDS specialists have
attacked the FDA guidelines, saying, "based on knowledge of
past cross-species transmissions, including AIDS, Herpes B
virus, Ebola, and other viruses, the use of animals has not
been adequately justified for use in a handful of patients
when the potential costs could be in the hundreds, thousands
or millions of human lives should a new infectious agent be
transmitted.”40 England has outlawed such transplants as too
dangerous.41 In humans, genetically engineered material can
enter the body through food or bacteria or viruses. The
dangers of lethal viruses containing genetically engineered
material and created by natural processes have been
mentioned above.
The dangers of generating pathogens by
vector mobilization and recombination are real. Over a
period of ten years, 6 scientists working with the genetic
engineering of cancer related oncogenes at the Pasteur
Institutes in France have contracted cancer.42 Non-human
engineered genes can also be introduced into the body
through the use of genetically engineered vaccines and other
medicines, and through the use of animal parts genetically
engineered with human genes to combat rejection problems.
Gene therapy, for the correction of defective human genes
that cause certain genetic diseases, involves the
intentional introduction of new genes into the body in an
attempt to modify the genetic structure of the body. It is
based on a simplistic and flawed model of gene function
which assumes a one-to-one correspondence between individual
gene and individual function. Since horizontal interaction43
among genes has been demonstrated, introduction of a new
gene can have unforeseen effects.
Another problem, already mentioned, is
the slippery slope that leads to the notion of designer
genes. We are already on that slope with the experimental
administration of genetically engineered growth hormone to
healthy children, simply because they are shorter than
average and their parents would like them to be taller.44
NOTES: 38. In the
People's Republic of China, Professor Chen Zhang-Liang,
Director of the National Laboratory of Protein Engineering
and Plant Genetic Engineering and Vice President, Peking
University, directs a laboratory "that is transplanting
human protein genes into tomatoes and sweet peppers to
control ripening. (Arthur Fisher, "A Long Haul for Chinese
Science" (Popular Science, Special Issue: Chinese Science
and Technology, August, 1996, p. 42.)
39. See "Surrogate Fathers," New
Scientist, January31, 1998.
40. IP/Biodiv News, 1-24-97. For further
information on the dangers of xenotransplants, see Alix Fano
et. al. "Of Pigs, Primates and Plagues: a Layperson's Guide
to the Problems with Animal-to-Human Organ Transplants," NY:
Medical Research Modernization Committee, n.d.
41. LONDON (AP) - Britain barred the
transplant of animal organs to humans on Thursday, saying
the risk of disease transmission must be better understood.
The decision came after a report by a government-appointed
panel of experts, which was chiefly concerned that animal
viruses in the transplanted organs could introduce new
diseases into humans.... Pigs are known to harbor several
retroviruses - the family of virus that includes HIV - one
of which was only discovered in the last two years. Research
has shown that some of them can infect animal cells in the
laboratory.... But Britain has made it clear that emergency
legislation will be brought in if necessary to halt human
trials.... The pigs are bred with human genes that cause
their organs to be coated with human molecules, which is
meant to prevent the most severe form of rejection in a
human patient.. .. (Associated Press, Jan. 16, 1997)
42. Ho (1996) reporting on information
from New Scientist (June 18, 1987): 29.
43. Horizontal gene transfer refers to
"the transfer of genes to unrelated species by infection
through viruses, through pieces of genetic material, DNA, by
being taken up into the cells from the environment, or by
unusual mating taking place between unrelated species.
(Mae-Wan Ho, Genetic Engineering: Dream or Nightmare, p. 13)
44. Andrew Kimbrell, The Human Body Shop
the Engineering and Marketing of Life (NY: HarperCollins,
1994), pp.142- $t 157.
44a. ibid, p. 191.
~ To be continued
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