Many genes on Laura’s inactive X are still active And since they are identical to each other and to Wolverine’s X, both she and Wolverine will have the same active X in each cell.īut of course, leave it to nature to complicate things. So in Laura Kinney’s case, it would seem that the extra X chromosomes shouldn’t matter. One X is shut off in each of Laura’s cells. ( Read here about how this causes Calico cats to get their interesting patterning). The choice for which X escapes shut-down happens randomly in each cell. (Actually, what really happens is that the “default” for X chromosomes are to all be shut down, and one X in each cell escapes this and stays “on.”) As you can see in the image below, this X inactivation makes it so she has just one working copy of each gene on the X. The cell’s solution is to shut down one of a woman’s X’s. It certainly is for extra copies of other, equally large chromosomes. There are so many more genes on the X that all those extra copies would probably be deadly. And that chromosome has many fewer genes than the X. There is a delicate balance in the body where you need to have the exact right number of each gene.įor example, the issues associated with Down syndrome happen because of an extra chromosome 21. The X chromosome codes for about a thousand genes, which is a lot. Unless the cell does something about this imbalance, there can be real problems. Women generally have two X chromosomes while men have just one. X inactivation evens out the number of genes It turns out some of Laura’s supposedly inactive X genes are still firing. And since her X’s are identical to Wolverine’s X, it doesn’t matter which is on and which is off in her cells.īut nothing in biology is so simple. As anyone who knows anything about biology will tell you, each cell turns off one X in females to equal out the amount of X genes between men and women. Of all of these differences, the least significant would seem to be Laura’s two X’s. All their chromosomes are exactly the same except her two X’s versus his X and Y. So we’ve concluded that Laura and Wolverine are almost identical twins. So, as a normally born child versus a clone, Wolverine and Laura may have many differences in how they use their DNA, even the parts that are identical. In fact, even identical twins with the exact same DNA differ in the way they use it. There are parts of this that are inherited, but much of it is due to environmental influence. This is called epigenetics and it has to do with how much of each gene is used in some cells versus others. (Image: Wikimedia)įinally, there are going to be some subtle differences in how each of them uses their DNA. This means she and Wolverine will have different mitochondrial DNA. Laura will get her mitochondria from the donor's egg. (So if Laura Kinney’s egg donor was the lead scientist, then they share some mtDNA!) Wolverine’s came from his own mother’s egg. Since cloning involved putting Wolverine’s DNA into an egg, Laura’s mtDNA came only from this donor egg. Because of the way cloning works, Laura has different mitochondrial DNA ( mtDNA) than Wolverine.Īll your mtDNA comes from your mother’s egg. There are some other, minor differences too. All three of them are identical, but the fact that she has two makes her different genetically. (Left: Wikipedia, Right: Pixy)Īnother difference is that Wolverine has one X chromosome and Laura has two. She was made to kill Wolverine, but ends up befriending him instead.

Laura Kinney, or X-23, was cloned from a sample of Wolverine’s DNA. So this single chromosome difference has the power to make Wolverine a man, and Laura a woman. For example, the SRY gene turns a female embryo into a male one. Wolverine has a Y chromosome, and Laura does not.Įven though the Y is tiny and has a lot fewer genes than any other chromosome, this difference matters. This is one reason Laura Kinney and Wolverine can’t really be called identical twins. This means that whatever the set of chromosomes is from this egg and sperm will be identical for both twins. Identical twins are split from the exact same egg fertilized by the exact same sperm. This is a lot more than the 50% that is typically shared between brothers and sisters.īut they can’t really be called identical twins, either. But much, much closer to identical twins. I would say Laura Kinney, or X-23, and Wolverine are somewhere between brother and sister and identical twins.

Wolverine clone x 23