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Why cannot we crossbreed Pig and Cat?

  1. Jun 28, 2015 #1
    Both Cat and Pig have 38 chromosomes, source:

    https://en.wikipedia.org/wiki/List_of_organisms_by_chromosome_count

    So, why we cannot crossbreed them? If we take Pig’s spermatozoon and Cat’s egg cell (or vice versa - Pig’s egg cell and Cat’s spermatozoon) and try to merge them what will happen? Can we in principle receive the zygote contained 19 chromosomes from Cat and 19 from Pig? I never heard this to be done, why? Maybe zygote will be formed, but then it dies?

    As far as I am aware the major reason is immunological intolerance between spermatozoon and egg cell belonging to different species – one cell will simply destroy other, right?

    Can we avoid this problem? Imagine that we have got Cat’s spermatozoon and Cat’s egg cell containing Pig’s 19 chromosomes (In order to do it we will have to remove Pig’s all 19 chromosomes from Pig’s egg cell and put them into Cat’s egg cell. As I know it is impossible now). We merge these two cells, then what? Will we receive Cig (Cat+Pig)? Will cellular differentiation occur? Do the various genes (half from Cat and the rest half from Pig) struggle with each other? :oldeyes:
     
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  3. Jun 28, 2015 #2

    Ryan_m_b

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    Having the same number of chromosomes is not sufficient on its own for viable crossbreeding. Indeed organisms with different numbers of chromosomes can breed, albeit with sterile offspring, such as between donkeys and horses. Aside from that there is the matter of how compatible the genetics of the animal are. In this case there is likely to be a great many number of genes present in one species but not the other. Without two functioning pairs of multiple genes it's unlikely the offspring will be viable.
     
  4. Jun 28, 2015 #3

    SteamKing

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    Also, who would want to cross a cat with a pig in the first place?
     
  5. Jun 30, 2015 #4

    Drakkith

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    Someone who enjoys stalking their bacon?

    Or should that be someone who enjoys being stalked by their bacon?
     
  6. Jun 30, 2015 #5

    SteamKing

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    A pig that purrs instead of oinks.
     
  7. Jul 1, 2015 #6
    Yes, I think the same, but still - is such approach possible from the technical point of view?
    Is anybody in the world working to solve this problem? :oldeyes:

    Is it absolutely necessary? One copy of one certain gene would not be enough? Yes, the offspring may not reach maturity, but at least such animal will be born
     
  8. Jul 1, 2015 #7

    SteamKing

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    You haven't established that the lack of a pig-cat hybrid is a problem which is worth solving. As cute as a purring pig would be, they would not be verrry cuddly. :eek: :rolleyes:
    And we already have cats which weigh several hundred pounds (they're called lions and tigers). :wink:
     
  9. Jul 1, 2015 #8

    DaveC426913

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    And how is this a good thing?

    Remember the conscientious scientist's mantra: Just because we can doesn't mean we should.
     
  10. Jul 2, 2015 #9
    It is possible to modify the DNA of one organism and insert sequences of other organism's DNA.
    For simple organisms this is quite commonly done for very practical reasons, such as modifying bacteria so that they produce valuable medicines.
    For more complex organisms and involving multiple genes, this would be very much more difficult, and is certainly not achievable with our present knowledge.
    Even of we did develop our knowledge and techniques to the point where it was actually doable, the characteristics of the resulting animal would remain very hard maybe impossible to predict,
    and I have to ask what exactly would be the purpose of producing a cat-pig anyway?
     
  11. Jul 2, 2015 #10

    Ygggdrasil

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    To some extent, researchers who are trying to clone extinct animals are doing this, although with species much more closely related than cats and pigs.

    With species as different as cats and pigs, there maybe genetic incompatibilities that could prevent such a "genome transplantation" from succeeding. For example, cats and pigs have different regulatory DNA sequences that control gene expression, meaning that transcription factors that may perform the same function in both species probably bind to different DNA sequences. Thus, if one were to place a pig genome into an enucleated cat egg cell, the cat transcription factors in the egg probably would not be able to turn on the correct set of genes in the pig genome to get the embryo to develop correctly.
     
  12. Jul 2, 2015 #11
  13. Jul 4, 2015 #12
    Isn't it obvious? When tired of farming Pork one might wish to produce Cork, with Prackling instead of Crackling.
    Try to bear in mind that agriculture is a varied and ever-developing discipline.
     
  14. Jul 4, 2015 #13
    You appear to have received a good crop of well-informed comment, so I omit most of my reactions. You might however ask yourself a few questions without my prompting, such as why having the same number of chromosomes should be any reason for crossing them. After all, there are at least hundreds of effectively unrelated mammals with matching numbers of chromosomes, some more distantly related than cats and pigs, and some of those haven't been mated either. There also are fishes, reptiles, invertebrates and plants with matching numbers; why not ask the same question about say, artichokes and aardvark?
    "Why?" is one of the most treacherous questions in philosophy and industry as well as science.
    As for the presumption that matching numbers of chromosomes might imply the possibility of their compatibility, that is about as optimistic as the assumption that because a particular model of submarine happened to have the same number of parts as some particular model of aircraft, that one could create a functional hybrid from the starboard parts of the one plus the port parts of the other. I do not deny that you might, so don't think that I am trying to discourage you (after all,they both contain screws, plates, and so on) but all the same, I ungrudgingly leave the experiment to you.
    Similarly, you will find that cats and pigs have considerable overlap of genes that not only match in function, (over 50% I believe) but are functionally so similar that they can be swapped. However, in many cases a change far smaller than a gene swap can be fatal.
     
    Last edited: Jul 4, 2015
  15. Jul 4, 2015 #14
    And sometimes with viable offspring because the chromosomes pieces fit against each other. That is why humans can have a fused chromosome despite our closest ape relatives (chimps and bonobos) having one more. IIRC there are species with variable chromosome number in the population, implying that for their chromosome arrangement it can't be a fitness problem (or that the species is splitting into subspecies by having incipient reproduction barriers).
     
    Last edited: Jul 4, 2015
  16. Jul 6, 2015 #15
    Chromosome number isn't sufficient for sexually breeding or artificially inseminating two different species. As noted already, chromosome length is different. During chromosome duplication, that might mean that each cell would get a different length strand. It also means that what each triplet is coding for won't necessarily match, leading to nonsense coding and misshaped proteins, if they generate any at all.

    We're getting better at gene splicing, but being able to insert a sequence doesn't always mean it's been inserted into a usable section of the chromosome. If you're looking for expression of a single trait, maybe a pig's snout on a cat, then it would probably be better to isolate those genes that control for it and splice just those, not the entire genetic code.

    You might even get away with merely inserting a new plasmid into the cell if all you want is a single protein or set of amino acids. For instance, pGM169/GL67A is a plasmid that British medical researchers were trying to insert into the lung cells of people suffering from cystic fibrosis. Not satisfactorily done on mature organisms, but if you were to do so at the fertilized egg stage, it should reproduce in every cell of the body.
     
  17. Jul 20, 2015 #16
    I do not think that scientists always follow this rule. :oldsmile:

    And what kind of special knowledge do we need to have for our purpose?


    At least – just to know what the human can do.

    Yes I understand that these problems will arise. But now I want to know – is everything described in my first post possible from the technical point of view? Can we move one certain nucleus? During cloning this is usually done as I know.

    I do not think that Aneuploidy and mutation has got something to do with implanting the nucleus.

    Well, when looking at this article in Wikipedia:

    https://en.wikipedia.org/wiki/List_of_organisms_by_chromosome_count

    I noticed that Pig and Cat had the same number of chromosomes and that’s why I asked about them.

    If I had necessary equipment I would conduct such experiment :oldwink:

    Which species do you mean? :oldeyes:

    Excuse me, but I do not understand this. Let’s imagine that Cig received chromosomes of various lengths, then what? Human receive 46 chromosomes from their parents with various length, right? Besides, I do not understand what triplets (that is the process connected with transcription) have got to do with chromosomes and their length.
     
  18. Jul 20, 2015 #17

    DaveC426913

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    And just because they don't doesn't mean they shouldn't. :biggrin:
     
  19. Jul 20, 2015 #18

    Ygggdrasil

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    I don't know if the experiment has been done, but I am doubtful it would work for many of the reasons others have mentioned in this thread.
     
  20. Jul 20, 2015 #19

    SteamKing

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    Which is a good reason to be thankful that such equipment is not generally available.

    Doing something "just to see if it can be done" is never a necessary, nor sufficient, reason to proceed.
     
  21. Aug 2, 2015 #20
    - Red howler monkeys have 47-49 chromosomes due to "due to different numbers of microchromosomes." It seems to be an odd system for gender determination which, well, works. http://www.ncbi.nlm.nih.gov/pubmed/1914523

    - Swamp wallaby have 11 chromosomes for male, 10 for female. Seems to be a similar XY variant system, just not as odd. http://link.springer.com/article/10.1007/s003359900459

    - Squirrel monkeys have the same number of chromosomes, but the centromere placement varies so morally they are different. OTOH there is some argument whether it is one species or several. http://placentation.ucsd.edu/sqmonkey.html
     
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