So, this is a two parter. I’ve heard that they can now make synthetic sperm from a womans bone marrow. I can’t remember where from, but it had something to do with general news reports and the like. But since I’m not sure, i guess my first question should be whether or not this is true…?
If it is…then what are the odds of identical twin ladies being able to give birth to a clone?? Is it possible at all? I’m mean, being identical, then they have the same dna, right? So whatever they get from one parent, they would get the other from the other (twin) parent.
My mind is baffled. I think of reason’s that they couldn’t at all, and reason’s as to why it is possible, though slim.
If you combine an egg cell and a sperm derived from the same donor, you will not get a clone of the donor. A clone is genetically identical to the donor. In producing mature egg cells and sperm, one chromosome of each chromosome pair is discarded in random fashion, thus each contain only half of the genetic information of the donor genome, but not the complementary halves. thus for some genes, although the donor had two slightly different copies, the offspring may inherit two copies of the same allel. thus the allelic diversity is reduced in the offspring compared to the donor.
You would get a ton of recessive genes in the offspring that weren’t necessarily in the original. It would be worse than incest. It wouldn’t be a clone, because the DNA wouldn’t match the original. Here’s an example.
Lucy has 100 pairs of dominant/recessive genes. If she were cloned, these 100 genes would be exactly the same in the clone. If sperm were fashioned from her bone marrow and she was impregnated by herself, some of these gene pairs would lack a dominant gene, some of them would lack the recessive gene, and some would remain paired the same way as the original.
As has been pointed out, we already have natural human cloning. My sisters are clones. But this isn’t cloning.
There are lots of organisms that can produce both male and female gametes, and self-fertilization can happen. Some of those organisms have mechanisms to prevent or discourage selfing, others don’t, and some are even obligate selfers.
Selfing is different than cloning, as Anaglyph explained, because your gametes are haploid while your somatic cells are diploid. Each gamete contains a different assortment of your genes. If the parent already has two identical copies of an allele, then the offspring will necessarily have the same two identical copies. But if a gene is heterozygous, meaning you have two different versions of the allele, then the offspring will have a 25% chance of getting two copies of one version, a 50% chance of being heterozygous, and a 25% chance of getting two copies of the other version.
This can be bad because the offspring therefore has a 25% chance of expressing any genetic disease the parent is a carrier for. And note that this is why inbreeding is considered undesireable, because related people are more likely to be carriers for the same genetic disease, and therefore their offspring are more likely to express the genetic disease.
There’s also a related concept…suppose you cloned an egg cell, so you had two eggs that were identical genetically, then fertilized them with different sperm. The resulting two offspring would be closer than siblings, but still not genetically identical clones. Clones are 100% related, siblings are 50% related, these individuals would be 75% related.
Wow, so now i feel dumb for not thinkin about the same woman, bone marrow and egg. That one should have been obvious. So, it wouldn’t be a clone, answer number 2 succesfully reached…but what about the whole synthetic sperm. I can’t remember where i heard it from. Anybody know if any of this is even possible?