Gene therapy and gene-based drugs are two ways we could benefit from our growing mastery of genetic science．But there will be others as well．Here is one of the remarkable therapies on the cutting edge of genetic research that could make their way into mainstream medicine in the coming years．
While it's true that just about every eell in the body has the instructions to make a complete human’ most of those instructions are inactivated，and with good reason：the last thing you want is for your brain cells to start churning out stomach acid or your nose to turn into a kidney．①The only time cells truly have the potential to turn into any and all body parts is very early in a pregnancy,when so-called stem cells haven’t begun to specialize．
Yet this untapped potential could be a terrific boon to medicine．Most diseases involve the death of healthv cells—brain cells in Alzheimer’s，cardiac cells in heart disease，pancreatic cells in diabetes，to name a few．If doctors could isolate stem cells，then direct their growth，they might be able to furnish patients with healthy replacement tissue．
It was incredibly difficult，but last fall scientists at the University of Wisconsin managed to isolate stem cells and get them to grow into neural，gut，muscle and bone cells．The process still can’t be controlled，and may have unforeseen limitations．But if efforts to understand and master stem-cell develoDment prove successful，doctors will have a therapeutic tool of incredible power．
The same applies to clonin9，which is really just the other side of the coin．True cloning'as first shown with Dolly the sheep two years a90，involves taking fl developed cell and reactivating the genome within。resetting its developmental instructions to a pristine state．Once that happens，the rejuvenated cell can develop into a full—fledged animal，genetically identical to its parent．
For agriculture，in which purely physical characteristics like milk production in a cow or low fat in a hog have real market value，biological carbon copies could become routine within a few years．⑦This past year scientists have done for mice and cows what Ian Witmut did for Dolly，and other creatures are bound to join the cloned menagerie in the coming year．
Human clonin9，on the other hand，may be technically feasible but legally and emotionally more difficult．Still，one day it will happen．The ability to reset body cells to a pristine，undeveloped state could give doctors exactly the same advantages they would get from stem cells：the potential to make healthy body tissues of all sorts。and thus to cure disease．④That could prove to be a true“miracle cure”． [447 words]
1．The author believes that______．
A．there will inevitably be human cloning in the coming year
B．the potential to make healthy body tissues is undoubtedly a blessing to human beings，考試大，元旦快樂！
C．it is illegal to clone any kind of creatures in the world
D．it is legal to clone any kind of creatures in the world except human
2．Which of the following statements is NOT TRUE according to this passage?
A．Nearly every cell in the human brain has the instructions to make a complete human.考試大
B．It is impossible for a eell in your nose to turn into a kidney．
C．It is possible to turn OUt healthy replacement tissues with isolated stem cells．
D．There will certainly appear some new kind of cloned animal in the near future．
3．According to this passage，______isn’t a step involved in true clonin9．
A．selecting a stem cell
B．taking a developed cell
C．reactivating the genome within the developed cell
D．resetting the developmental instructions in the cell to its original state
4．In the author’s opinion，the potential of a cell to turn into any body parts is ______．
A．negligible
B．inactivated
C．worth tapping
D．beyond question
5．The proper title for this passage should be______．
A．Tomorrow’s Tissue Factory
B．A Terrific Boon to Medicine
C．Human Cloning
D．Genetic Research
While it's true that just about every eell in the body has the instructions to make a complete human’ most of those instructions are inactivated，and with good reason：the last thing you want is for your brain cells to start churning out stomach acid or your nose to turn into a kidney．①The only time cells truly have the potential to turn into any and all body parts is very early in a pregnancy,when so-called stem cells haven’t begun to specialize．
Yet this untapped potential could be a terrific boon to medicine．Most diseases involve the death of healthv cells—brain cells in Alzheimer’s，cardiac cells in heart disease，pancreatic cells in diabetes，to name a few．If doctors could isolate stem cells，then direct their growth，they might be able to furnish patients with healthy replacement tissue．
It was incredibly difficult，but last fall scientists at the University of Wisconsin managed to isolate stem cells and get them to grow into neural，gut，muscle and bone cells．The process still can’t be controlled，and may have unforeseen limitations．But if efforts to understand and master stem-cell develoDment prove successful，doctors will have a therapeutic tool of incredible power．
The same applies to clonin9，which is really just the other side of the coin．True cloning'as first shown with Dolly the sheep two years a90，involves taking fl developed cell and reactivating the genome within。resetting its developmental instructions to a pristine state．Once that happens，the rejuvenated cell can develop into a full—fledged animal，genetically identical to its parent．
For agriculture，in which purely physical characteristics like milk production in a cow or low fat in a hog have real market value，biological carbon copies could become routine within a few years．⑦This past year scientists have done for mice and cows what Ian Witmut did for Dolly，and other creatures are bound to join the cloned menagerie in the coming year．
Human clonin9，on the other hand，may be technically feasible but legally and emotionally more difficult．Still，one day it will happen．The ability to reset body cells to a pristine，undeveloped state could give doctors exactly the same advantages they would get from stem cells：the potential to make healthy body tissues of all sorts。and thus to cure disease．④That could prove to be a true“miracle cure”． [447 words]
1．The author believes that______．
A．there will inevitably be human cloning in the coming year
B．the potential to make healthy body tissues is undoubtedly a blessing to human beings，考試大，元旦快樂！
C．it is illegal to clone any kind of creatures in the world
D．it is legal to clone any kind of creatures in the world except human
2．Which of the following statements is NOT TRUE according to this passage?
A．Nearly every cell in the human brain has the instructions to make a complete human.考試大
B．It is impossible for a eell in your nose to turn into a kidney．
C．It is possible to turn OUt healthy replacement tissues with isolated stem cells．
D．There will certainly appear some new kind of cloned animal in the near future．
3．According to this passage，______isn’t a step involved in true clonin9．
A．selecting a stem cell
B．taking a developed cell
C．reactivating the genome within the developed cell
D．resetting the developmental instructions in the cell to its original state
4．In the author’s opinion，the potential of a cell to turn into any body parts is ______．
A．negligible
B．inactivated
C．worth tapping
D．beyond question
5．The proper title for this passage should be______．
A．Tomorrow’s Tissue Factory
B．A Terrific Boon to Medicine
C．Human Cloning
D．Genetic Research