ANNIVERSARIO 20 ANNI DALLA CLONAZIONE DELLA PECORA DOLLY / 20 YEARS ANNIVERSARY FROM THE CLONING OF SHEEP DOLLY
SEGNALATO DAL DR. GIUSEPPE
COTELLESSA (ENEA) / REPORTED BY DR. GIUSEPPE COTELLESSA (ENEA)
Venti anni dopo la pecora Dolly,
che fine ha fatto la clonazione?
Il 5 luglio 1996 nasceva la
pecora Dolly, il primo mammifero concepito con una tecnica di clonazione a
partire da cellule di ghiandola mammaria di un esemplare adulto. Vent'anni
dopo, le applicazioni della tecnica sono ben lontane dalle previsioni di
allora, e limitate agli animali di allevamento, mentre la clonazione di un essere
umano è stata scongiurata più per motivi etici che per motivi tecnici.
Dolly tuttavia dimostrò che anche le cellule di mammifero possono essere
riprogrammate, aprendo la strada a importanti progressi nel campo della ricerca
sulle cellule staminali. Era una bellissima giornata di 20 anni fa quando Ian
Wilmut e Alan Trounson, scienziati, colleghi e vecchi amici, partirono per
un'escursione sulle colline intorno a Edimburgo, in Scozia. Di fronte al
panorama della città, Wilmut confidò di avere un segreto da rivelare.
Nell'ambito di uno studio più ampio, lui e alcuni collaboratori erano riusciti
a far nascere un agnello in laboratorio. Non da una cellula uovo e da uno
spermatozoo, bensì dal DNA estratto dalla ghiandola mammaria di una pecora
adulta: avevano clonato un mammifero. “Diamine, ero sbalordito”, racconta
Trounson, che, oggi come allora, lavora sulle cellule staminali presso la
Monash University di Melbourne, in Australia. Era una giornata calda, ma
Trounson sentì ugualmente un brivido lungo la schiena quando si rese conto
delle implicazioni del risultato. “Da allora tutto cambiò”. La clonazione di un
mammifero sfidava il dogma scientifico imperante a quel tempo. Il successo
portò a previsioni fosche e fantastiche: anche gli umani sarebbero stati
clonati. Le malattie sarebbero state sconfitte. I bambini persi durante la
gravidanza sarebbero rinati. Oggi, due decenni dopo la nascita di Dolly,
avvenuta il 5 luglio del 1996, l'impatto della clonazione sulla scienza di base
ha superato le aspettative, mentre la realtà di ciò che tecnicamente si
chiama trasferimento nucleare, la forma di clonazione utilizzata per Dolly, è
in gran parte scomparsa dalla scena pubblica.
Venti anni dopo la pecora Dolly, che fine ha fatto la clonazione?La
pecora Dolly imbalsamata, esposta al National Museum of Scotland (Wikimdia
Commons)
Nel 2016, la clonazione di una
persona rimane irrealizzabile, priva di qualunque beneficio scientifico e
gravata da un livello di rischio inaccettabile, dicono molti scienziati.
Nessuno, a quanto pare, sta pensando di cimentarsi in questa impresa (? NDR). E
la clonazione di animali rimane limitata, anche se probabilmente è in aumento.
Alcune tecniche di clonazione agricola sono utilizzate negli Stati Uniti e in
Cina per sfruttare i geni di alcuni esemplari straordinari, dicono gli scienziati,
mentre il Parlamento europeo ha votato l'anno scorso il divieto di utilizzare
la clonazione negli animali destinati all'alimentazione umana. Uno scienziato in Corea del Sud fa
pagare 100.000 dollari per clonare un animale domestico, anche se non è chiaro
quale sia il livello della domanda di questo servizio. Il maggiore impatto
della clonazione, dicono diversi ricercatori, è visibile nei progressi ottenuti
nel campo delle cellule staminali. Il biologo cellulare ed esperto di staminali
Shinya Yamanaka ha spiegato che la clonazione di Dolly lo spinse a iniziare a
sviluppare le cellule staminali derivate da cellule adulte, un risultato che
gli valse il premio Nobel nel 2012. "La pecora Dolly mi fece capire che la
riprogrammazione nucleare era possibile anche in cellule di mammiferi e
m'incoraggiò a iniziare il mio progetto, ha scritto Yamanaka, che si divide tra
l'Università della California a San Francisco, e il Center for iPS Cell
Research and Application (CIRA) dell'Università di Kyoto, in Giappone, di cui è
direttore. Yamanaka usò cellule adulte di topo, anche se la tecnica è ora
adatta anche alle cellule umane, per produrre staminali in grado di dare vita a
una vasta gamma di altre cellule, essenzialmente riportando indietro i loro
“orologi cellulari” fino all'infanzia in modo che potessero maturare in diversi tipi di
cellule adulte.
Poiché sono create
artificialmente e possono avere diversi destini, esse sono chiamate cellule
staminali pluripotenti indotte o cellule iPS. Queste cellule iPS, sempre più
facilmente disponibili, hanno ridotto la necessità di cellule staminali
embrionali, il cui utilizzo ha sollevato molte questioni etiche, e attualmente
costituiscono la base per la maggior parte della ricerca sulle staminali. La
nascita di Dolly è stata foriera di grandi cambiamenti, perché ha dimostrato
che il nucleo della cellula adulta ha tutto il DNA necessario per dare luogo a
un altro animale, dice il biologo cellulare Robin Lovell-Badge, a capo della
divisione di Biologia delle cellule staminali e di Genetica dello sviluppo
presso il Francis Crick Institute di Londra. In precedenza, alcuni
ricercatori avevano ottenuto rane adulte da cellule di rana embrionali o
cellule di rana embrionali da rane adulte, arrivando a una fase di stallo. "Quello
di Dolly è stato il primo caso in cui si è presa una cellula adulta per
ottenere un individuo adulto", sottolinea Lovell-Badge. "Questo
significava poter riprogrammare un nucleo di cellula adulta per tornare a uno
stadio embrionale."
Venti anni dopo la pecora Dolly, che fine ha fatto la
clonazione?Campioni di cellule iPS in laboratorio: lo sviluppo delle tecniche
per ottenerle è uno degli effetti della clonazione della pecora Dolly (Credit:
Commonwealth Scientific and Industrial Research Organisation, CSIRO)
Dolly morì il 14 febbraio del
2003, all'età di sei anni, per un'infezione polmonare comune tra gli animali
che non hanno accesso all'aria aperta. Probabilmente la malattia non aveva niente
a che fare con il fatto di essere un animale clonato, dice Wilmut, ora
professore emerito presso il Roslin Institute dell'Università di Edimburgo.
La pecora, ottenuta da cellule
della mammella, deve il nome alla famosa Dolly Parton, cantante americana nota
per il suo prosperoso seno oltre che per la sua voce. "Non era nostra
intenzione essere irrispettosi verso la signora in questione o le donne in
generale", ha dichiarato Wilmut recentemente commentando il nome, che fu
suggerito da un allevatore. Piuttosto, ha contribuito a umanizzare un progetto
di ricerca che altrimenti sarebbe potuto sembrare distaccato dalla vita di
tutti i giorni. “La scienza e la sua presentazione a volte possono sembrare
terribilmente serie", ha detto. "Penso che sia stato un bene per noi:
ci ha fatto apparire umani".
Wilmut ammette che la nascita di
Dolly è stata un caso fortunato. Lui e i suoi colleghi stavano cercando di
produrre cloni di cellule fetali e usavano quelle adulte come controlli
sperimentali, senza aspettarsi la generazione di un embrione. "Non avevamo
deciso di clonare cellule adulte, ma solo di lavorare idealmente con cellule
staminali embrionali o cose del genere”, dice Wilmut. “Avere successo con le cellule
adulte è stato un bonus inatteso e di grande valore. “L'obiettivo
iniziale della ricerca di utilizzare il sistema di produzione di latte di un
animale come una sorta di fabbrica per ottenere proteine utili al trattamento
di malattie umane. Ma l'interesse per questa idea è diminuito con la produzione
sempre più massiccia di sostanze chimiche di sintesi a basso costo.
Wilmut ritiene che clonare un
essere umano sarebbe possibile, ma fortemente sconsigliato. La tecnica
di clonazione utilizzata per Dolly ha dimostrato di non funzionare sui primati.
Egli
ritiene che potrebbe essere possibile utilizzando altre tecniche, ma si oppone
con veemenza all'idea di clonare una persona. “Il solo fatto che ora la
tecnica consenta di produrre una progenie non implica che dovremmo farlo”,
dice. “È probabile che si otterrebbero aborti e malformazioni nei
neonati".
Per esempio, uno degli agnelli
clonato nel suo laboratorio subito dopo Dolly ha sviluppato problemi ai polmoni
che si manifestavano con iperventilazione e continui svenimenti. “Già vederlo
in un animale è stato piuttosto sconfortante", continua. “Non vorrei mai
essere nei panni di una persona che si trova a guardare negli occhi un bambino
per scusarsi”. Con i recenti progressi nella tecnologia di editing genetico, la
necessità della clonazione per correggere gli errori genetici si ridurrà ancora
di più", osserva Wilmut. "Ci sono ancora meno motivi per farlo
rispetto a prima”.
Trounson ritiene che per gli
embrioni di bestiame clonati vi sia un mercato enorme. “Può essere
sorprendente, ma sono in molti a usarli, cercando di non farsi notare troppo”,
spiega. “I vantaggi sono per l'eccellenza della produzione, e aumentare i
parametri di produzione è una cosa molto positiva", aggiunge Trounson, che
recentemente si è dimesso, dopo sei anni, dall'incarico di presidente del California
Institute for Regenerative Medicine, un ente statale che fornisce prestiti e
sovvenzioni per la ricerca sulle cellule staminali. "Questo è
probabilmente il fattore decisivo che spinto molte aziende a restare negli
Stati Uniti".
Nel 2008, il governo degli Stati
Uniti ha stabilito che non vi fossero differenze distinguibili tra vacche,
capre e maiali clonati e non clonati, e ha perciò consentito la produzione di
questi animali, soprattutto per la produzione di mangimi piuttosto che di
carne. In Cina una società chiamata Boyalife Group ha in programma di ottenere
almeno 100.0000 bovini da carne clonati, che rappresentano solo una parte del
totale di animali macellati ogni anno nel paese, come spiega un portavoce
dell'azienda. "Potrebbe essere questo il momento migliore per far
progressi nell'applicazione di questa tecnica da un punto di vista sia
tecnologico sia commerciale".
Venti anni dopo la pecora Dolly, che fine ha fatto la
clonazione?Rappresentazione artistica di un mammut: tra le tante applicazioni
immaginate per la clonazione, vi è anche quella di riportare in vita specie
estinte o in via di estinzione (Wikimedia commons)
In teoria, la clonazione potrebbe
anche essere utilizzata per salvaguardare le specie in pericolo. Si è parlato
di usarla per riportare in vita i mammut, i panda giganti e perfino l'Uomo di
Neanderthal, ma si tratta di idee che Lovell-Badge liquida come
"abbastanza stupide". Trounson sostiene di avere ancora una scorta di
campioni di pelle di vombati, in pericolo critico di estinzione, conservati
nell'azoto liquido, nel caso in cui qualcuno volesse mai tentare di
ripristinare le popolazioni di questa specie. I cloni, tuttavia, sono creati
prendendo una cellula adulta e fondendola con una cellula uovo ricevente.
Produrre un clone richiede un nucleo intatto, che non sarebbe disponibile per
la maggio parte delle specie estinte.
Diversi ricercatori stanno ora
utilizzando tecniche di clonazione per produrre cellule staminali embrionali,
evitando così la necessità di raccogliere nuovi embrioni. Il cosiddetto trasferimento
nucleare da cellula somatica può aiutare i ricercatori a capire meglio le fasi
precoci dell'embriogenesi umana e la biologia delle cellule staminali,
secondo Paul Knoepfler, biologo dell'Università della California a Davis, che
non era coinvolto direttamente nel lavoro. Knoepfler ha scritto via e-mail che
non "vede alcun beneficio terapeutico imminente, ma le cose in futuro
potrebbero cambiare".
L'idea di clonare un caro
defunto, sia esso umano o animale, è invece caduta in disgrazia, in parte
perché è difficile disconoscere l'influenza dell'ambiente sul comportamento. La
componente genetica potrebbe essere la stessa, ma un clone sarebbe ancora lo
stesso individuo che abbiamo amato? “Non sarà mai possibile riavere indietro il
vostro Fufi, o qualunque altra cosa”, sottolinea Lovell-Badge, aggiungendo che
l'idea di clonare un animale domestico “è stupida”. “L'unico caso a cui si
potrebbe vagamente pensare”, conclude, “è quello di un cane particolarmente
prezioso”, per esempio dotato di un super-olfatto: in questo caso gli
scienziati potrebbero essere interessati a chiarire se si tratta di una qualità
innata o appresa.
Lovell-Badge è ancora più
sprezzante verso l'idea di clonare una persona. “Dovremmo conoscere molte più cose
sulla riprogrammazione ed essere in grado di eseguirla con un'efficacia del 100
per cento”, spiega. “E non ho mai trovato una ragione sufficiente per
clonare un essere umano."
ENGLISH
Twenty years after Dolly the sheep, what happened to the clone?
On July 5, 1996 was born Dolly the sheep, the first mammal conceived with a cloning technique from the mammary gland cells of an adult specimen. Twenty years later, the applications of the technique are far from that time predictions, and limited to farmed animals, while the cloning of a human being has been averted more for ethical reasons than for technical reasons. Dolly, however, showed that mammalian cells can be reprogrammed, paving the way for major advances in the field of stem cell research. It was a beautiful day 20 years ago when Ian Wilmut and Alan Trounson, scientists, colleagues and old friends, set out for a hike in the hills around Edinburgh, Scotland. In front of the panorama of the city, Wilmut told to have a secret to reveal. As part of a larger study, he and several co-workers were able to give birth to a lamb in the laboratory. Not from an egg cell and a sperm, but from the DNA extracted from the mammary gland of an adult sheep: they had cloned a mammal. "Heck, I was stunned," says Trounson, which, then as now, is working on stem cells at Monash University in Melbourne, Australia. It was a hot day, but also Trounson felt a shiver down his spine when he realized the implications of the result. "Since then everything changed." The cloning of a mammal challenged the scientific dogma prevalent at that time. The success led to dire predictions and fantastic: even humans were cloned. Disease would be defeated. The children lost during pregnancy would be reborn. Today, two decades after the birth of Dolly, which took place on July 5, 1996, the impact of cloning on basic science has exceeded expectations, while the reality of what is technically called nuclear transfer, the form used to clone Dolly , it has largely disappeared from the public eye.
In 2016, the cloning of a person remain unachievable, devoid of any scientific benefit and burdened by an unacceptable level of risk, say many scientists. No one, it seems, is planning to engage in this enterprise (? NDR). And the cloning of animals is limited, although it is probably increasing. Some agricultural cloning techniques are used in the United States and China to exploit the genes of some extraordinary specimens, scientists say, while the European Parliament voted last year banning the use of cloning in animals intended for human consumption. A scientist in South Korea does pay $ 100,000 to clone a pet, although it is not clear what the level of demand for this service. The greatest impact of cloning, say several researchers, is visible in the progress achieved in the field of stem cells. The cell biologist and expert on stem Shinya Yamanaka explained that the cloning of Dolly prompted him to start developing stem cells derived from adult cells, an achievement that earned him the Nobel Prize in 2012. "Dolly the sheep made me realize that nuclear reprogramming was also possible in mammalian cells and encouraged me to start my project, wrote Yamanaka, who divides his time between the University of California at San Francisco, and the Center for iPS cell Research and Application (CIRA) of ' University of Kyoto, Japan, of which he is director. Yamanaka used adult cells of mice, even though the technique is now also suitable to human cells, to produce stem cells capable of giving rise to a wide range of other cells, essentially bringing back their "cellular clock" until childhood so they could mature into different types of adult cells.
Since they are artificially created and can have different destinies, they are called induced pluripotent stem cells or iPS cells. These iPS cells, becoming more readily available, have reduced the need for embryonic stem cells, whose use has raised many ethical questions, and now form the basis for the majority of stem cell research. The birth of Dolly was a harbinger of great change, because it showed that the nucleus of the adult cell DNA has everything you need to give rise to another animal, says cell biologist Robin Lovell-Badge, head of the Cell Biology Division stem and developmental genetics at the Francis Crick Institute in London. Previously, researchers had obtained adult frogs from frog embryonic cells or embryonic frog cells from adult frogs, coming to a standstill. "What Dolly was the first case in which she took an adult cell to get an adult," emphasizes Lovell-Badge. "This meant we could reprogram an adult cell nucleus back to an embryonic stage."
Dolly died Feb. 14 of 2003, at the age of six years, for lung infection common among animals that have no access to fresh air. Probably the disease had nothing to do with the fact that a cloned animal, says Wilmut, now professor emeritus at the Roslin Institute of Edinburgh University.The sheep, obtained from breast cells, owes its name to the famous Dolly Parton, American singer known for her breasts as well as her voice. "It was not our intention to be disrespectful towards the lady in question, or women in general," said Wilmut recently commenting on the name, which was suggested by a breeder. Rather, it has helped to humanize a research project that otherwise might have seemed detached from everyday life. "The science and its presentation can sometimes seem terribly series," he said. "I think it was good for us, made us seem human."Wilmut admitted that the birth of Dolly was a lucky accident. He and his colleagues were trying to produce fetal cells and adult clones and used as experimental controls, without expecting the generation of an embryo. "We had not decided to clone adult cells, but only to work ideally with embryonic stem cells or anything like that," says Wilmut. "Being successful with adult cells was an unexpected bonus and great value." The initial objective of search of the use of a milk animal production system as a kind of factory to obtain useful proteins to the treatment of human diseases. But the interest in this idea is decreased with the increasingly massive production of chemicals of low-cost synthesis .Wilmut believes that it would be possible to clone a human being, but strongly discouraged. The cloning technique used for Dolly has proven not to work on primates. He believes that it may be possible using other techniques, but is vehemently opposed to the idea to clone a person. "The sole fact that technology now allows to produce offspring does not mean we should do it," he says. "It is likely that you would get abortions and birth defects."For example, one of the cloned sheep Dolly in his laboratory just after he developed lung problems which manifested themselves with hyperventilation and continuous fainting. "You see it in an animal has been pretty gloomy," he continues. "I would never want to be in the shoes of a person who is looking into the eyes a child to apologize." With recent advances in gene editing technology, the need for cloning to correct genetic errors still reduce more, "says Wilmut. "There are even fewer reasons to do so than before."Trounson believes that for cattle embryos cloned there is a huge market. "It may be surprising, but there are many who use them, trying not to get noticed too," he explains. "The benefits are for the excellence of the production, and increase the production parameters is a very positive thing," adds Trounson, who recently stepped down after six years, from the post of president of the California Institute for Regenerative Medicine, a state agency that provides grants and loans for stem cell research. "This is probably the decisive factor that led many companies to remain in the United States."the production of these animals, especially for the production of feed, rather than meat in 2008, the US government has established that there were no discernible differences between cows, goats and pigs cloned and non-cloned, and has therefore allowed. In China, a company called Boyalife Group has plans to get at least 100.0000 beef cattle cloned, representing only part of the total number of animals slaughtered every year in the country, explains a company spokesperson. "This could be the best time to make progress in the application of this technique both from a technological point of view it is commercial".
In theory, the cloning may also be used to preserve endangered species. There has been talk of using it to revive mammoths, giant pandas and even the Neanderthal, but these are ideas that Lovell-Badge liquid as "pretty stupid." Trounson claims to still have a stock of the wombats skin samples, critically endangered, preserved in liquid nitrogen, in case someone wants to ever groped to restore the populations of this species. The clones, however, are created by taking an adult cell and fusing it with a receiving egg cell. To produce a clone requires a nucleus intact, that would not be available for the May part of the extinct species.Several researchers are now using cloning techniques to produce embryonic stem cells, thus avoiding the need to collect new embryos. The so-called somatic cell nuclear transfer may help researchers better understand the early stages of human embryogenesis and stem cell biology, according to Paul Knoepfler, biologist at the University of California at Davis, who was not directly involved in the work. Knoepfler wrote via e-mail that does not "see any imminent therapeutic benefit, but things could change in the future."The idea of cloning a deceased loved one, be it human or animal, has instead fallen into disfavor, in part because it's hard to ignore the influence of environment on behavior. The genetic component may be the same, but a clone would still be the same person that we loved? "It will never be possible to get back your Fufi, or anything else", says Lovell-Badge, adding that the idea to clone a pet "is stupid." "The only case in which it might vaguely think", concludes, "is that of a particularly valuable dog", for example equipped with a super-smell: in this case, scientists might be interested to clarify whether it is of a quality innate or learned.
Lovell-Badge is even more contemptuous of the idea to clone a person. "We should know a lot more about reprogramming and be able to perform it with an efficacy of 100 per cent," he explains. "And I've never found a good enough reason to clone a human being."
On July 5, 1996 was born Dolly the sheep, the first mammal conceived with a cloning technique from the mammary gland cells of an adult specimen. Twenty years later, the applications of the technique are far from that time predictions, and limited to farmed animals, while the cloning of a human being has been averted more for ethical reasons than for technical reasons. Dolly, however, showed that mammalian cells can be reprogrammed, paving the way for major advances in the field of stem cell research. It was a beautiful day 20 years ago when Ian Wilmut and Alan Trounson, scientists, colleagues and old friends, set out for a hike in the hills around Edinburgh, Scotland. In front of the panorama of the city, Wilmut told to have a secret to reveal. As part of a larger study, he and several co-workers were able to give birth to a lamb in the laboratory. Not from an egg cell and a sperm, but from the DNA extracted from the mammary gland of an adult sheep: they had cloned a mammal. "Heck, I was stunned," says Trounson, which, then as now, is working on stem cells at Monash University in Melbourne, Australia. It was a hot day, but also Trounson felt a shiver down his spine when he realized the implications of the result. "Since then everything changed." The cloning of a mammal challenged the scientific dogma prevalent at that time. The success led to dire predictions and fantastic: even humans were cloned. Disease would be defeated. The children lost during pregnancy would be reborn. Today, two decades after the birth of Dolly, which took place on July 5, 1996, the impact of cloning on basic science has exceeded expectations, while the reality of what is technically called nuclear transfer, the form used to clone Dolly , it has largely disappeared from the public eye.
In 2016, the cloning of a person remain unachievable, devoid of any scientific benefit and burdened by an unacceptable level of risk, say many scientists. No one, it seems, is planning to engage in this enterprise (? NDR). And the cloning of animals is limited, although it is probably increasing. Some agricultural cloning techniques are used in the United States and China to exploit the genes of some extraordinary specimens, scientists say, while the European Parliament voted last year banning the use of cloning in animals intended for human consumption. A scientist in South Korea does pay $ 100,000 to clone a pet, although it is not clear what the level of demand for this service. The greatest impact of cloning, say several researchers, is visible in the progress achieved in the field of stem cells. The cell biologist and expert on stem Shinya Yamanaka explained that the cloning of Dolly prompted him to start developing stem cells derived from adult cells, an achievement that earned him the Nobel Prize in 2012. "Dolly the sheep made me realize that nuclear reprogramming was also possible in mammalian cells and encouraged me to start my project, wrote Yamanaka, who divides his time between the University of California at San Francisco, and the Center for iPS cell Research and Application (CIRA) of ' University of Kyoto, Japan, of which he is director. Yamanaka used adult cells of mice, even though the technique is now also suitable to human cells, to produce stem cells capable of giving rise to a wide range of other cells, essentially bringing back their "cellular clock" until childhood so they could mature into different types of adult cells.
Since they are artificially created and can have different destinies, they are called induced pluripotent stem cells or iPS cells. These iPS cells, becoming more readily available, have reduced the need for embryonic stem cells, whose use has raised many ethical questions, and now form the basis for the majority of stem cell research. The birth of Dolly was a harbinger of great change, because it showed that the nucleus of the adult cell DNA has everything you need to give rise to another animal, says cell biologist Robin Lovell-Badge, head of the Cell Biology Division stem and developmental genetics at the Francis Crick Institute in London. Previously, researchers had obtained adult frogs from frog embryonic cells or embryonic frog cells from adult frogs, coming to a standstill. "What Dolly was the first case in which she took an adult cell to get an adult," emphasizes Lovell-Badge. "This meant we could reprogram an adult cell nucleus back to an embryonic stage."
Dolly died Feb. 14 of 2003, at the age of six years, for lung infection common among animals that have no access to fresh air. Probably the disease had nothing to do with the fact that a cloned animal, says Wilmut, now professor emeritus at the Roslin Institute of Edinburgh University.The sheep, obtained from breast cells, owes its name to the famous Dolly Parton, American singer known for her breasts as well as her voice. "It was not our intention to be disrespectful towards the lady in question, or women in general," said Wilmut recently commenting on the name, which was suggested by a breeder. Rather, it has helped to humanize a research project that otherwise might have seemed detached from everyday life. "The science and its presentation can sometimes seem terribly series," he said. "I think it was good for us, made us seem human."Wilmut admitted that the birth of Dolly was a lucky accident. He and his colleagues were trying to produce fetal cells and adult clones and used as experimental controls, without expecting the generation of an embryo. "We had not decided to clone adult cells, but only to work ideally with embryonic stem cells or anything like that," says Wilmut. "Being successful with adult cells was an unexpected bonus and great value." The initial objective of search of the use of a milk animal production system as a kind of factory to obtain useful proteins to the treatment of human diseases. But the interest in this idea is decreased with the increasingly massive production of chemicals of low-cost synthesis .Wilmut believes that it would be possible to clone a human being, but strongly discouraged. The cloning technique used for Dolly has proven not to work on primates. He believes that it may be possible using other techniques, but is vehemently opposed to the idea to clone a person. "The sole fact that technology now allows to produce offspring does not mean we should do it," he says. "It is likely that you would get abortions and birth defects."For example, one of the cloned sheep Dolly in his laboratory just after he developed lung problems which manifested themselves with hyperventilation and continuous fainting. "You see it in an animal has been pretty gloomy," he continues. "I would never want to be in the shoes of a person who is looking into the eyes a child to apologize." With recent advances in gene editing technology, the need for cloning to correct genetic errors still reduce more, "says Wilmut. "There are even fewer reasons to do so than before."Trounson believes that for cattle embryos cloned there is a huge market. "It may be surprising, but there are many who use them, trying not to get noticed too," he explains. "The benefits are for the excellence of the production, and increase the production parameters is a very positive thing," adds Trounson, who recently stepped down after six years, from the post of president of the California Institute for Regenerative Medicine, a state agency that provides grants and loans for stem cell research. "This is probably the decisive factor that led many companies to remain in the United States."the production of these animals, especially for the production of feed, rather than meat in 2008, the US government has established that there were no discernible differences between cows, goats and pigs cloned and non-cloned, and has therefore allowed. In China, a company called Boyalife Group has plans to get at least 100.0000 beef cattle cloned, representing only part of the total number of animals slaughtered every year in the country, explains a company spokesperson. "This could be the best time to make progress in the application of this technique both from a technological point of view it is commercial".
In theory, the cloning may also be used to preserve endangered species. There has been talk of using it to revive mammoths, giant pandas and even the Neanderthal, but these are ideas that Lovell-Badge liquid as "pretty stupid." Trounson claims to still have a stock of the wombats skin samples, critically endangered, preserved in liquid nitrogen, in case someone wants to ever groped to restore the populations of this species. The clones, however, are created by taking an adult cell and fusing it with a receiving egg cell. To produce a clone requires a nucleus intact, that would not be available for the May part of the extinct species.Several researchers are now using cloning techniques to produce embryonic stem cells, thus avoiding the need to collect new embryos. The so-called somatic cell nuclear transfer may help researchers better understand the early stages of human embryogenesis and stem cell biology, according to Paul Knoepfler, biologist at the University of California at Davis, who was not directly involved in the work. Knoepfler wrote via e-mail that does not "see any imminent therapeutic benefit, but things could change in the future."The idea of cloning a deceased loved one, be it human or animal, has instead fallen into disfavor, in part because it's hard to ignore the influence of environment on behavior. The genetic component may be the same, but a clone would still be the same person that we loved? "It will never be possible to get back your Fufi, or anything else", says Lovell-Badge, adding that the idea to clone a pet "is stupid." "The only case in which it might vaguely think", concludes, "is that of a particularly valuable dog", for example equipped with a super-smell: in this case, scientists might be interested to clarify whether it is of a quality innate or learned.
Lovell-Badge is even more contemptuous of the idea to clone a person. "We should know a lot more about reprogramming and be able to perform it with an efficacy of 100 per cent," he explains. "And I've never found a good enough reason to clone a human being."
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http://www.lescienze.it/news/2016/07/07/news/clonazione_20_anni_dopo_pecora_dolly-3152306/
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