May 08, 2014
Thoroughbred Horses Not Getting Any Faster
Did you know that the international body that regulates thoroughbred racing lifted its ban against clones in 2012? Secretariat could ride again. Thoroughbreds aren't getting any faster. How boring.
Faster is better. I would like to see new race horses bred using many horse breeds rather than just thoroughbreds. Next I'd like to sequencing of millions of horses to identify genetic variants that are purely harmful. This is known as genetic load. Then do extensive genetic testing and sequencing of the edited cell lines to make sure no bad genetic edit happened.
Then try CRISPR genetic editing on embryos to get rid of the genetic load. The result would be horses that could beat Secretariat.
What would be ways better: Identify all the genetic load mutations in a group of fertile humans. Then edit out the genetic load of their embryos. The result would be super humans. Super humans would be brilliant and extremely healthy.
In another 10 or so years might be a lower risk way to cut down genetic load in humans: Take dozens of sample skin cells from a man, preferably from areas with little sun exposure (so less genetic damage from the sun). Grow up each sample in a separate cell culture. Genetically test cells from each culture to identify the least genetically damaged ones. To the ones with little genetic damage do CRISPR genetic editing to get rid of every known harmful mutation (and in 10 yearrs we will know thousands of harmful mutations if not more). Then turn the cells into sperm cells. The babies would have no paternal genetic load.
Your own cells genetically edited in culture to fix all their genetic load mutations would have another big benefit: They'd be great starting points for creating cell therapies. Send in new muscle cell precursors that can function better than your own muscles did when you were young. Grow a better kidney, liver, or pancreas than you ever had. Fix whatever has given you a skin condition, an easily upset stomach, or easily injured tendons. The cell therapies would be like a software update embedded in a hardware update.
Randall Parker, 2014 May 08 09:55 PM
At first glance the possibility of editing out the genetic load seems to be helpful, but at the same time, I wonder if some of the features contained in this so-called genetic load has unknown benefits that help in other areas: we still need to be careful in not removing necessary components inadvertently.
Interesting info with some good basics. And Wolf-Dog hit the major point. Some traits that are deleterious in some/most situations are beneficial in others. Whether the gene is heterozygous or homozygous, 2 different genes at the same location or the same gene doubled up can be a factor. Sickle cell anemia being the most well known. If hetero, gives resistance to malaria, if homoz for either sickle cell or normal blood, either so impaired with blood that the person dies early or if not affected with sickle cell dies of malaria. Check out heterozygous superiority.
This article also doesn't take into account epigenetics. How 'nurture' influences nature. Epigenetics is not mutations from ultraviolet light or other causes but how the genes respond to chemical exposure, illness, exercise, diet, with methyl tags that affect genetic expression. Identical twins start with the same risk factors but by the time they are I think reach 50, their epigenetic profiles may change so much that they are effectively no more at risk than fraternal siblings.
Next is that many traits are polygenic. The interaction of several genes at various sites. Some genes modulate the expression of others. Another factor is Copy Number Variations. Either deletions in a gene site or more than one copy of a gene stacked up at a site. The early data on this was so shocking that the researchers thought they were errors. Which genes are activated, are several active and to what degree? Possible those others act as reserve software copies in case the active copy becomes a corrupted file. :)Genetic imprinting also affects genetic expression. Mules and hinnies are both crosses of a horse and a donkey but look a bit different. Mules have a donkey jack sire and mare dam, hinnies a stallion and a jenny. Mules are overall preferred and are sturdier. Ligers/tigons are crosses of lions and tigers. Depending on which was the mother, size can vary by hundreds of pounds.
And what is 'better' or optimal will depend what the human does in life. Available diet, lifestyle, exposure to environmental toxins and common illnesses. etc.
No matter if a 'perfect' baby is born, when s/he produces ovum or sperm, there will be mutations. Each of us carries roughly 60 genes that are somewhat different than our parents. That perfect genome will be at least a bit different in the next generation.
But genetic technology does promise many wide ranging benefits IF we can avoid hubris. Not too long ago the meme was one gene one effect. Monsanto loved that meme and used it as a way to encourage gene patenting.
Fur farmers trying to breed for the best red fur color in foxes ran into the polygenic problem mentioned by data junkie. It's a good way to give the unwary a headache, trying to follow the combinations. This was discovered about 40 years ago?
I suspect Randall is familiar with the concerns mentioned above. Put simply, the fact that genetics is complicated doesn't preclude the fact that any random mutation is simply bad.
Pleiotropy, epigenetics, CNVs, balanced polymorphisms -- these are all interesting, complicating factors. But there's plenty that is unambiguously broken in our genomes, and we would likely gain great benefit by fixing it.
http://www.macarthurlab.org/lof for more on how to identify this 'genetic load'...
I don't understand this concept. How do genes evolve to kill you?
Sounds like that's still unclear, based on the Wikipedia article:
"Traditionally, discussion of the cause of their extinction has focused on the antler size (rather than on their overall body size), which may be due more to their impact on the observer than any actual property...Simply blaming antler size for their extinction may not be entirely accurate. The most likely cause is the significantly shortened growing season seen toward the end of the Pleistocene Era. This reduced availability in nutrition resulted in the lowering of the female reproduction output by about 50%."
map: One way would be genetic optimization for a given environment, and the environment changes.