| From: John Devers ® | 18/07/2001
16:35:21 |
| Subject: Cloning between species. |
post id:
353261 |
| Has anyone ever tried to take the
nucleus of a cell from one species and place it in place of the nucleus in
the egg of another species? Can you cross speciate in this way or does the same problem exist as with sperm? What actually genetically stops species from successfully mating and producing offspring? | |
| From: ferret | 18/07/2001
17:29:20 |
| Subject: re: Cloning between species. |
post id:
353389 |
It's a good question. Not really in my field but since no-one else has had a go, I'll swing the bat at it. The short answer might be that cloning is difficult enough already, within the same species. Maybe inter-species cloning will be on the agenda later on. I do know that, for cell duplication, there has to be interaction and coordination between the intranuclear and the extranuclear (cytoplasmic) components of the cell. For instance, in DNA replication, a substance called tRNA is required for lining up the DNA building blocks. tRNA is made in the cytoplasmia reticulum, outside the nucleus. I'm not sure that tRNA from one species could work with DNA from another. For protein manufacture, ribosomes are involved and they are also a cytoplasmic component. I personally doubt that interspecies cloning would work. (And I shudder to imagine what the attempts would look like.) Maybe someone with greater depth of knowledge could provide a more precise answer. | |
| From: Chris B | 18/07/2001
17:33:19 |
| Subject: re: Cloning between species. |
post id:
353397 |
| That really is an interesting
thought. Apparently Dolly took about 30 or more attempts before success so you could imagine how hard it would be to go interpecies. Some species may mix, as we all know - Mules etc... but they then cannot produce more offspring themselves so there is a definite genetic block working there somewhere... | |
| From: Carmel ® | 18/07/2001
17:38:58 |
| Subject: re: Cloning between species. |
post id:
353409 |
| Has anyone ever
tried to take the nucleus of a cell from one species and place it in place
of the nucleus in the egg of another species? Not to my knowledge, but I suspect that they may have been attempts with plants... hmmm... Theoretically, if the species were closely related, it shouldn't be a problem... It might be more difficult with distantly related organisms. What actually genetically stops species from successfully mating and producing offspring? Each organism has a unique number of chromosomes (even). When gametes (a sperm and egg) from two different organisms hook up then we have the problem that there are chromosomes left over without a partner. This means they cannot properly form their own gametes and are therefore infertile. In some instances, these hybrids my not actually survive past the zygote stage (a fertilized egg), others, like a mule or liger may be viable, just infertile. | |
| From: John Devers ® | 18/07/2001
17:51:21 |
| Subject: re: Cloning between species. |
post id:
353431 |
| Looks like there might be a
sudden evolution burst in the next few years if there are no barriers
preventing the process. I'm sure someone will try it in the next few weeks. Doesn't the latest process with two women just expel the unwanted extra genetic material with the addition of a drug. Wouldn't it be the same with two species? | |
| From: Purple | 18/07/2001
18:32:45 |
| Subject: re: Cloning between species. |
post id:
353463 |
| I think they've done it with
plants...but maybe I was dreaming :) Didn't someone like Joseph Banks start with cross-pollinating plants? | |
| From: Carmel ® | 18/07/2001
18:36:43 |
| Subject: re: Cloning between species. |
post id:
353465 |
| I think they've
done it with plants...but maybe I was dreaming :) I have that trouble all the time. Didn't someone like Joseph Banks start with cross-pollinating plants? Cross-pollination is a little different. It usually involves plants that are relatives. Plants genomes are also a little funkier than mammalian genomes. | |
| From: Kinase ® | 18/07/2001
18:55:59 |
| Subject: re: Cloning between species. |
post id:
353478 |
| Going back to the tRNAase thing.
I suspect that these chemicals may be the same or similar for most
species. They have been doing genome mapping for a large number of species
- they would have to use different restriction and multiplication enzymes
for each sp. if they were different (I din;t think they do). Also, viruses
and some bacteria can fiddle with our DNA/RNA - and some can be virulent
on a number of species. So I would think that tRNA etc is pretty similar
between sp. Any expert comments? there is also mitochondrial DNA which could stuff up the inter sp. cloning. Kinase | |
| From: Carmel ® | 18/07/2001
19:02:59 |
| Subject: re: Cloning between species. |
post id:
353483 |
| I suspect that
these chemicals may be the same or similar for most species.
Some, but not all. I can think of at least one or two human specific tRNA's that mean it's frightfully difficult to make recombinant proteins unless you introduce the correct tRNA. If you put human DNA into, say, a horse cell, you would want to ensure you also supplied those tRNAs, somehow (maybe pre-injecting the cell with a plasmid encoding the correct tRNA so it could express it before the human genome went in). there is also mitochondrial DNA which could stuff up the inter sp. cloning. I imagine they would include human mitochondria into the soup, in a similar way to the use of two women's eggs to make a child... | |
| From: Kinase ® | 18/07/2001
19:09:41 |
| Subject: re: Cloning between species. |
post id:
353491 |
| And what of the cell membrane?
Would that remain the same as the original cell, or become like the donor
DNA's cell membrane (as the DNA codes to make new cell membrane from its
own little code). If the cell membrane remained the same as the original
sp., then would you run into massive problems with cell recognition,
hormone action,
immuno-response? Kinase | |
| From: pigman ® | 18/07/2001
19:49:25 |
| Subject: re: Cloning between species. |
post id:
353539 |
| Dolly took a lot more than 30
attempts, try three replicates of around 250 attempts, of course not all
of these developed into viable embryos | |
| From: J.F. ® | 18/07/2001
19:51:44 |
| Subject: re: Cloning between species. |
post id:
353541 |
| tRNA is made in
the cytoplasmia reticulum, outside the nucleus. I'm not sure that tRNA
from one species could work with DNA from another This is not quite right. tRNA must be coded for by DNA. tRNA is used in protein synthesis on the endoplasmic (not cytoplasmia) reticulum, (AFAIK it is not made there). I had not realised, until I read this thread, that some (nuclear) tRNA are species-specific. I mean, I knew that mitochondria used a different genetic code... read about it decades ago. I had assumed that the tRNA anticodons from one species is very likely to work in another, and that the amino acid-binding end would work too. Well, that's one reason I like coming here; I learn all the time :)) | |