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2011 Marek Vácha. Totipotence u rostlin "renucleated cell"

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Prezentace na téma: "2011 Marek Vácha. Totipotence u rostlin "renucleated cell""— Transkript prezentace:

1 2011 Marek Vácha

2 Totipotence u rostlin

3 "renucleated cell"

4 Reprodukční klonování tým Iana Wilmuta vytváří ovci Dolly v roce 1996 To get Dolly, the Scottish scientists transferred 277 adult nuclei into sheep eggs, implanted 29 clonal embryos, and achieved the birth of only one live lamb clone

5  Dolly was born after 276 failures

6 Compaction  Shortly after formation of 8 cells (around four days after fertilization), the blastomeres remain loosely connected to one another  Soon afterward, they huddle together, maximizing their contact with one another and forming a compact balls of cells

7 Compaction  This tighly packed arrangement is stabilized by tight junctions that form between the outside cells of the ball, sealing off the inside of the sphere  the cells of the compacted embryo divide to produce a 16-cell morula  (Gilbert, S.C., Tyler, A.L., Zackin, E.J., (2005) Bioethics and the New Embryology. Sinauer Associates, Inc. W.H. Freeman & comp. Sunderland, MA U.S.A. p. 14)

8 Morula  consists of a small group of internal cells surrounded by a larger group of external cells  descendants of the exterior cells become trophoblast cells  trophoblast cells form tissue of the chorion, the embryonic portion of the placenta  inner cells generate inner cell mass (ICM)  ICM will give rise to the embryo and its associates yolk sac, allantois and amnion

9 Terapeutické a reprodukční klonování

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12 Reprodukční klonování  1996 ovce  1997 myš  1998 kráva  2000 prase  2002 kočka  2005 pes

13  cloned animals have also be re-cloned, and clones have reproduced sexually, although many cloned males are sterile (the earliest succesful clones were all female)  K.C., a cow cloned at the University of Georgia from the cell af a dead cow, gave birth in December 2004 to Sunshine, a calf who seems normal in every way  (Pierce, J., Randels, G., (2010) Contemporary Bioethics. Oxford University Press, NY, Oxford. p. 260)

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15 Úmluva o lidských právech a biomedicíně  Dodatkový protokol  Článek 1  1. Každý zákrok, jehož účelem je vytvořit lidskou bytost, která je geneticky shodná s jinou lidskou bytostí, živou či mrtvou, je nepřípustný  2. Pro účely tohoto článku výraz „geneticky shodná“ lidská bytost s jinou lidskou bytostí znamená lidskou bytost, která má s jinou lidskou bytostí společný jaderný soubor genů

16 VYSVĚTLUJÍCÍ ZPRÁVA K DODATKOVÉHO PROTOKOLU K ÚMLUVĚ NA OCHRANU LIDSKÝCH PRÁV A DŮSTOJNOSTI LIDSKÉ BYTOSTI V SOUVISLOSTI S APLIKACÍ BIOLOGIE A MEDICÍNY O ZÁKAZU KLONOVÁNÍ LIDSKÝCH BYTOSTÍ  3.Záměrné klonování lidí představuje ohrožení lidské svébytnosti, neboť by mohlo vyústit ve vzdání se nepostradatelné ochrany před předurčením lidské genotypové sestavy třetí stranou. Další etické odůvodnění zákazu klonování lidských bytostí založeno především na lidské důstojnosti, která je zásahy ve formě umělého klonování lidí ohrožena. (…) Vzhledem k tomu, že přirozeně se projevující nová genetická kombinace pravděpodobně dává lidské bytosti více svobody než předurčená genetická sestava, je v zájmu všech lidí, aby byl zachován v podstatě náhodný charakter složení jejich vlastních genů.

17 UNESCO: Universal Declaration on the Human Genome and Human Rights 11 November 1997  nonbinding Universal Declaration on the Human Genome and Human Rights

18 UNESCO: Universal Declaration on the Human Genome and Human Rights 11 November 1997  Article 11 Practices which are contrary to human dignity, such as reproductive cloning of human beings, shall not be permitted. States and competent international organizations are invited to co-operate in identifying such practices and in taking, at national or international level, the measures necessary to ensure that the principles set out in this Declaration are respected.

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20 Argumenty pro reprodukční klonování  The last year the luminaries of the International Academy of Humanism—including biologists Crick, Dawkins, and Wilson and humanists Isaiah Berlin, W. V. Quine, and Kurt Vonnegut—issued a statement in defense of cloning research in higher mammals and humans beings. Their reasons are revealing:  What moral issues would human cloning raise? Some world religions teach that human beings are fundamentally different from other mammals.... Human nature is held to be unique and sacred. Scientific advances which pose a perceived risk of altering this “nature” are angrily opposed.... [But] [a]s far as the scientific enterprise can determine... [h]uman capabilities appear to differ in degree, not in kind, from those found among the higher animals. Humanity’s rich repertoire of thoughts, feelings, aspirations, and hopes seems to arise from electrochemical brain processes, not from an immaterial soul that operates in ways no instrument can discover.... Views of human nature rooted in humanity’s tribal past ought not to be our primary criterion for making moral decisions about cloning.... The potential benefits of cloning may be so immense that it would be a tragedy if ancient theological scruples should lead to a Luddite rejection of cloning. (International Academy of Humanism, 1997.)

21 Argumenty pro reprodukční klonování  if a woman had a serious mitochondrial disorder, she could become pregnant with a donated oocyte (which would supplied the mitochondria) into which a nucleus of one of her or her partner´s somatic cells had been transplanted

22 Argumenty pro reprodukční klonování  To allow an infertile couple to have a child The Italian doctor Severino Antinori wants to offer cloning as a treatment for infertility. Critics have pointed out that anyone who was a clone of one of their parents would be under unknown psychological pressures throughout their childhood. Would they feel they were living up to the achievements of their 'original'? And how would a woman feel about bringing up a much younger version of the person she fell in love with? To bring back a child killed in an accident In recent years, some bereaved families have contacted scientists asking them to clone a dead child. However, even if human cloning was possible, families might be distraught to discover their new baby was not exactly like their dead older brother or sister - and the 'replacement' child might suffer feelings of inferiority about being born purely to take the place of their dead sibling.  To replicate the talents of exceptional human beings If Mother Theresa or Einstein could be genetically reproduced, their clones might choose very different paths in life, and disappoint the people who had chosen to create them. Out of curiosity or to attempt some sort of immortality The scientist Richard Dawkins has expressed the desire to clone himself out of pure curiosity. Immortality through cloning seems an impossible goal because the clone’s experiences and thoughts would be their own, not those of the cloned adult. To obtain a supply of stem cells The stem cells would be taken from a cloned embryo and used to rejuvenate and repair our bodies. The embryo would then be destroyed.

23 Arguments against reproductive cloning  cloned humans may face problems of identity and individuality  because they are genetically identical to people who already lived, and there may be expectations to be like their predecessors  cloning could contribute to the commodification of children and the commercialization of reproduction  cloning could lead to eugenics, favoring particular genetic traits  family relations might be confused, such as if the father and son were genetic twins, this also "brothers"  there might be a slippery slope impact on society, leading to such things as genetic enhancement and genetic control over the next generation

24 Arguments against reproductive cloning  argument of "an open future"  by choosing a child´s genetic makeup in advance, parents deny the child´s right to an open future  reprodukční klonování likviduje rodiny - kam a ke komu by vlastně dítě mělo patřit?  kdo je bratr či sestra dítěte?

25 Argumenty proti reprodukčnímu klonování  neumíme to technicky  člověk má mít end-in-herself a nesmí se stát prostředkem  VIZ ale beztrestní rodiče, kteří od 2 – 3 let dělají ze svých dětí gymnastky, hokejisty nebo tenisty

26 Argumenty proti reprodukčnímu klonování  it is ironic that those who believe that you can´t stop science, present themselves as wise to the ways of the world, yet understand so little of how science really works. It is they, not those who believe cloning can be banned, who are the naïve idealists  (King, D., (2003) Cloning? Yuk! In: Key Issues in Bioethics. (eds) Levinson, R., and Reiss, M.J., London, RotledgeFalmer, pp )

27 Argumenty proti reprodukčnímu klonování  As Harvard philosopher Hilary Putnam put it: "Every child has the right to be a complete surprise to its parents"  Jewish perspective: the glory of creation is that unity in heaven creates diversity on earth.  Sacks, J., (2009) Genesis: The Book of Beginnings. Covenant and Coversation. Maggid Books and The Orthodox Union. New Milford, USA, London, Jerusalem. p. 150

28 Argumenty proti reprodukčnímu klonování  cloning is a radical form of child abuse  Asexual reproduction, which produces "single parent" offspring, is indeed a radical departure from the natural human way, confounding all normal understandings of father, mother, sibling, grandparent and the like, and all oral relations tied thereto.  (Kass, R.L., (2002) Life, Liberty and Defense of Dignity. Encounter Books, New York, London. p. 150,154)

29 Argumenty proti reprodukčnímu klonování  cloning threatens confusion of identity and and individulality, even in small-scale practice  cloning represents a giant step toward transforming procreation into manufacture, that is, toward the increasing depersonalization of the process of generation and toward the "production" of human children as articfacts, products of human will and design  cloning - like other forms of eugenic engineering of the next generation - represents a form of despotism of the cloners over the cloned, and thus a blatant violation of the inner meaning of parent-child relations, of what it means to have a child, of what it means to say "yes" to our own demise and "replacement"  (Kass, R.L., (2002) Life, Liberty and Defense of Dignity. Encounter Books, New York, London. p. 150,154)

30 Argumenty proti reprodukčnímu klonování  Can anyone really give an argument fully adequate to the horror that is father-daughter incest (even with consent)(...) or the eating of human flesh? (...) Would anybody´s failure to give full rational justificatin for his revulsion at those practices make that revulsion ethically suspect? Not at all.  (Kass, R.L., (2002) Life, Liberty and Defense of Dignity. Encounter Books, New York, London. p. 150,154)

31 Argumenty proti reprodukčnímu klonování  the power of sexuality is rooted in its strange connection to mortality, which it simultaneously accepts and tries to overcome. Asexual reproduction may be seen as a continuation of the activity of self-preservation.  (Kass, R.L., (2002) Life, Liberty and Defense of Dignity. Encounter Books, New York, London. p. 150)  in all higher animals, reproduction as such implies both the acceptance of the death of self and participation in its transcendence. The salmon, willingly swimming upstream to spawn and die, makes vivid this universal truth.

32 Argumenty proti reprodukčnímu klonování  No family dynamic is likely to be unaffected by the fact that the cloned chld will have a special relationship to only one of his or her parents. And what will hapen when the adolescent clone of Mommy becomes the spitting image of the woman with whom Daddy once fell in love? In case of divorce, will Mommy still love the clone of Daddy, even though she can no longer stand the sight of Daddy himself?  (Kass, R.L., (2002) Life, Liberty and Defense of Dignity. Encounter Books, New York, London. p. 159)

33 Argumenty proti reprodukčnímu klonování  Whereas most parents normally have hopes for their children, cloning parents will have expectations, indeed, will likely have a plan. The child is given a genotype that has already lived, with full expectation that this blueprint child now means a child who exists precisely to fulfill parental wants.  (Kass, R.L., (2002) Life, Liberty and Defense of Dignity. Encounter Books, New York, London. p. 159)

34 Hans Jonas, 1974 (proti reprodukčnímu klonování): “Všimněme si, že se nejedná o to, co je genotyp pro osobu ve skutečnosti; jedná se o to, že genotyp je učiněn osudem osoby, tím, že je klonován. Nezáleží na to, zda ovšem okrást člověka, který má vzniknout o svobodu je zločin, kterého se nesmíme v ani jednom případě dopustit.“ genotyp v sobě zahrnuje zopakování života osoby: jedinec vznikl s touto ideou, a tato představa je ve svém důsledku tyranická. Nezáleží na tom, jaký je skutečný vztah nature – nurture. Existenčně důležité je to, co si klonovaná osoba myslí – co je jí vnucováno si myslet – o sobě. Ještě před svým narozením je tak okradena o svobodu. Tato svoboda by se snad mohla projevit pouze v případě nevědomosti;

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