Tweet
mtDNA transpant in primates
...could humans be next? Ethical questions aside, it could repair many genetic disorders. On the other hand it creates a child with 3 parents: two nuclear and one mitochondrial.
Changing A Cell's Biological Battery
A new method tested in monkeys for replacing mitochondrial DNA could one day prevent devastating diseases.
Mitochondrial diseases, which affect as many as one in 4,000 people, can impair muscles, nerves, even entire organ systems, and have no known cure. Now, in a breakthrough study, Oregon researchers replaced defective mitochondrial DNA with that from a healthy donor. The first subjects, four baby monkeys, are pushing the envelope on the ethical debate that surrounds bioengineering.
>
Shoukhrat Mitalipov and his colleagues at Oregon Health & Science University in Beaverton, OR, have found a way to get rid of mutant mtDNA. Using a process similar to cloning, they first harvested a fertile egg. Then, when the egg was undergoing cell division, they removed a set of its chromosomes and inserted them into an egg harvested from another female, one that already had its nucleus removed. In essence, the enucleated egg provided a set of mitochondrial chromosomes, while the transferred nuclear chromosomes provided the main genetic material for development. Other researchers have attempted similar processes, but previous efforts couldn't prevent mutant mitochondria from tagging along to the new egg.
>
"It's an important study, and it's the only approach that I can think by which you could render a family free of risk of their offspring developing a mitochondrial DNA disease," says Douglas Wallace, a mitochondrial DNA researcher at the University of California, Irvine. Because mitochondrial DNA is self-replicating, the technique allows for a way to "swap" healthy versions for mutant ones without genetic alterations.
But therein also lies the rub. Many researchers and ethicists alike balk at the idea of making genetic changes to the germline, ones that fundamentally affect an egg or sperm and will be passed along to the next generation. While swapping out mitochondrial DNA may not qualify as the kind of germline engineering people have in mind when they worry about made-to-order babies--with certain traits like intelligence or eye color specifically engineered--it edges toward that shaky ethical ground.
>
>2nd page continues...
A new method tested in monkeys for replacing mitochondrial DNA could one day prevent devastating diseases.
Mitochondrial diseases, which affect as many as one in 4,000 people, can impair muscles, nerves, even entire organ systems, and have no known cure. Now, in a breakthrough study, Oregon researchers replaced defective mitochondrial DNA with that from a healthy donor. The first subjects, four baby monkeys, are pushing the envelope on the ethical debate that surrounds bioengineering.
>
Shoukhrat Mitalipov and his colleagues at Oregon Health & Science University in Beaverton, OR, have found a way to get rid of mutant mtDNA. Using a process similar to cloning, they first harvested a fertile egg. Then, when the egg was undergoing cell division, they removed a set of its chromosomes and inserted them into an egg harvested from another female, one that already had its nucleus removed. In essence, the enucleated egg provided a set of mitochondrial chromosomes, while the transferred nuclear chromosomes provided the main genetic material for development. Other researchers have attempted similar processes, but previous efforts couldn't prevent mutant mitochondria from tagging along to the new egg.
>
"It's an important study, and it's the only approach that I can think by which you could render a family free of risk of their offspring developing a mitochondrial DNA disease," says Douglas Wallace, a mitochondrial DNA researcher at the University of California, Irvine. Because mitochondrial DNA is self-replicating, the technique allows for a way to "swap" healthy versions for mutant ones without genetic alterations.
But therein also lies the rub. Many researchers and ethicists alike balk at the idea of making genetic changes to the germline, ones that fundamentally affect an egg or sperm and will be passed along to the next generation. While swapping out mitochondrial DNA may not qualify as the kind of germline engineering people have in mind when they worry about made-to-order babies--with certain traits like intelligence or eye color specifically engineered--it edges toward that shaky ethical ground.
>
>2nd page continues...
Comment