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Asked by cheesecakegirl to Adam, Joanna, Louise S, Marcus on 22 Nov 2012.
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Joanna Giles answered on 22 Nov 2012:
The liger and the tiglon you talk about are indeed a crosses between a tiger and a lion. And these only exist in captivity because in the wild the habitats would not overlap and so a tiger would not normally meet a lion in the wild. There are other crosses like mules – which is a cross of a donkey and a horse, but these are actually sterile and cannot reproduce themselves.
Crossing humans and apes? A bit more wacky, but you are right because humans and apes have a huge percentage of DNA similarities, and actually people have been thinking about it for over a 100 years. There are rumours that it has been attempted between a human and a chipamzee (with 98% similar DNA to a human) and an offspring would be called a “Humanzee” (a cross between a human and a chipanzee). Years ago an ape called “Oliver” was thought to have been one of these humanzees because he was a chip with amazingly human features. However, when his DNA was analysed they concluded he was a regular chimp. People still debate whether it would be possible, and I think generally people think it might be possible but because of ethical issues I don’t think it will ever be attempted.
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Marcus Wilson answered on 22 Nov 2012:
lions and tigers are classfied as different species but the same genus, the next catagory up. even so its pretty weird, ofetn this cant happen and most of the time the offspring is infertile ( like a ule form donkey and horse)
you cant bread humans and apes because we are two dissimiliar. we evolved away from apes far before tigers evolved from lions.
we did, however, bread with one fo our closely related ancestors, the neanderthals. originally no one thought this was possible but when we sequenced the neanderthal genome ( form theri bones), we found some similiarties that suggetsed cross breeding!
most people of european descent have a couple of percent neanderthal DNA in them now! -
Adam Paige answered on 22 Nov 2012:
One thing that makes this difficult is a very strange idea called imprinting. We have our 30,000 genes grouped on 46 DNA molecules (called chromosomes). These are actually 23 pairs of chromosomes, where one set of 23 comes from our fathers and the other set from our mothers. We used to believe that the copy of each gene we got from our fathers is switched on in us, and so was the copy we get from our mothers. For most genes this is true. But some genes are imprinted. This means the DNA of those genes contains lots of methyl (CH3) groups on one of the two copies. This methylation switches the gene off. So it is a way of making sure that for these imprinted genes, only one of the two copies is actually working in our cells. What is really weird though is that it is always the same copy. Some genes are always switched off on the copy inherited from the father, and others are always switched off on the copy inherited from the mother. Which means our genes “remember” which of our parents each of the two copies came from! What is more, if the imprinting is not done correctly it can cause serious diseases in us. There was a visiting professor who lectured at my university this week on the subject. He suggests that problems with the imprint on the chromosomes from our mothers could cause schizophrenia, whilst problems with the imprint on the chromosomes from our fathers could cause autism.
If the correct balance between the chromosomes from each of our parents has to be maintained to avoid disease, then consider how difficult it would be to get chromosomes from two different species to work properly in a cell to allow a cross-breed child to be born.
Comments
Joanna commented on :
I don’t think you can say that you “can’t” because it hasn’t been done (I hope anyway!!).
Also did you know you can breed a horse with a zebra? -> a Zebroid – very cute!