pig embryo

theguardian.com
First human-pig 'chimera' created in milestone study
Prospect of growing human organs for transplantation raised by creation of first ever embryos combining two large, distantly related species
By Hannah Devlin

Scientists have created a human-pig hybrid in a milestone study that raises the prospect of being able to grow human organs inside animals for use in transplants.

It marks the first time that embryos combining two large, distantly-related species have been produced. The creation of this so-called chimera – named after the cross-species beast of Greek mythology – has been hailed as a significant first step towards generating human hearts, livers and kidneys from scratch.

Juan Carlos Izpisua Belmonte, who led the work on the part-pig, part-human embryos at the Salk Institute for Biological Studies in La Jolla, California, said: “The ultimate goal is to grow functional and transplantable tissue or organs, but we are far away from that. This is an important first step.”

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The federal government announced plans Thursday to lift a moratorium on funding of certain controversial experiments that use human stem cells to create animal embryos that are partly human.

The National Institutes of Health is proposing a new policy to permit scientists to get federal money to make embryos, known as chimeras, under certain carefully monitored conditions.

The NIH imposed a moratorium on funding these experiments in September because they could raise ethical concerns.

One issue is that scientists might inadvertently create animals that have partly human brains, endowing them with some semblance of human consciousness or human thinking abilities. Another is that they could develop into animals with human sperm and eggs and breed, producing human embryos or fetuses inside animals or hybrid creatures.

But scientists have argued that they could take steps to prevent those outcomes and that the embryos provide invaluable tools for medical research.

NIH Plans To Lift Ban On Research Funds For Part-Human, Part-Animal Embryos

Photo: Pablo Ross of the University of California, Davis, inserts human stem cells into a pig embryo as part of experiments to create chimeric embryos. Rob Stein/NPR

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Researchers genetically engineered a pig embryo to grow with some human cells.

anonymous asked:

Okay so explain to me developmental biology? Since I clearly don't know what I'm talking about.

well, first you thought that cells aren’t living simply because there’s no brain nor heart. It’ll be interesting to see your face when you find out that a plethora of organisms on earth don’t have brains nor hearts and yet are living. For example, every plant that has ever existed and will ever exist. Clearly a brain and a heart are not determinants of life. However, biology has conducted a check list for what constitutes as living. 

1)Living things are made of cells.

2)Living things obtain and use energy.

3)Living things grow and develop.

4)Living things reproduce.

5)Living things respond to their environment.

6)Living things adapt to their environment

So, let’s go over what you said

>an embryo has no heart or brain. how is it considered a “living” being. 

well, anon, an embryo has no heart and no brain, but as we can see above, that is not a condition for living things. An embryo is a multicellular diploid eukaryote that is usually before the 8th week of prenatal development (scientists may argue that it’s between the 3rd and 8th weeks and prior to the third, it’s the blastocyst). How does this mean it’s living though, you ask? Well, first off, it’s multi-cellular, meaning it’s made of cells, so condition 1 is met. Does it obtain energy and use energy though? considering that an embryo/blastocyst is made of cells (remember multicellular?) and are eukaryotes that use mitochondria, which generates and Adenosine Triphosphate (ATP) for the cell to use, i’m almost certain these cells are obtaining and using energy. But what about the organism itself? yes, studies of other embryos (pig in this case) show the embryo uses glucose through the process of glycolysis. Human’s are probably extremely similar. Do they grow and develop? of course. The embryo itself is growing rapidly in the beginning stages of prenatal life. Does it reproduce? oh ho, you got me anon, this organism cannot reproduce, but mind you, no organism can reproduce in the early stages of development. Children cannot reproduce until puberty. This certainly does not mean that a child up to age 9-14 are not living. Mind you the embryo is the extreme early stages of human development and not an organism of a different species in it’s own right. Through human development, two haploid gametes come together to form a zygote. This zygote is of the human species and thus human. It is not a bacterium or some other eukaryotic cell, with some magic dust becomes a human. So, the embryo may not be able to reproduce, but fully developed, it can (fully developed is an adult human). But can the embryo respond and adapt to the environment? well, just as reproduction is more geared toward fully developed organisms, these two more so relate to organisms over time. The first is really responding to stimuli can be defined in many ways because of how organisms can respond. Single celled organisms can respond to an environment through homeostasis among other ways. An embryonic organism can respond in these ways. This is also similar to adapting. 

So, yes, an embryo is living. 

>if so, every time you have taken an antibiotic, you killed off cells of your own body. So what’s the difference in killing one of those cells and killing a germ cell or a stem cell?

Well, umm. you’re wrong because antibiotics either kill or inhibit bacterial growth and they don’t kill our own cells. Dr. Harry Mobley, chair of the department of microbiology and immunology at the University of Michigan Medical School, explains why. But in any case, let’s say there’s a medicine of some sort that actually does kill your own cells (as opposed to inhibiting reproduction). So what’s the difference between using this drug (or whatever) to kill my own cells vs a bacterium vs a stem cell. 

Okay, my own cells are not humans. I do not have ~ 100,000 billion little humans that make up a big human. My skin cells, bone cells, T-cells, etc are simply just that. If they die, it’s not killing a human. The combination of everything is the result of a multicellular human organism (me). The killing of a few cells does not kill a human. It’s only the killing of a human that denotes ethical problems. Bacterium, on the other hand, are prokaryotic single celled organisms. These cells are, in their own right, full and separate organisms (as opposed to the different cells of a multicellular eukaryote). E. Coli, for example, is an entire organism that is one cell. Killing one cell of E. Coli is actually killing a full organism. Why isn’t that ethically wrong? It’s not a human. What about stem cells? These cells are unspecialized cells within a mulitcellular organism. They are not organisms of themselves being they are part of a larger organism. An embryo is not a stem cell. In order to obtain embryonic stem cells, you have to destroy the embryo. As we went over, the embryo is a living organism and also a human. Destroying a human to further science isn’t exactly ethical.