Back to David's theory of evolution (Evolution)

by David Turell , Monday, July 13, 2020, 19:20 (1592 days ago) @ David Turell

dhw: I would suggest that the complexity of the immune system has evolved “layer upon layer” as the cells have created their own defences against disease after disease, gradually building up a library of responses. I have doubts about an all-powerful God who finds it impossible to create a system without errors, while clever humans manage to correct his errors.

DAVID: Again totally illogical. Not God's errors but errors of life's functioning molecules

Here is an article on correcting molecular errors in mitochondrial DNA:

https://www.sciencenews.org/article/mitochondria-gene-editing-bacterial-toxin-crispr

"A protein secreted by bacteria to kill other microbes has been re-engineered to tweak DNA inaccessible to other gene editors, scientists report online July 8 in Nature. The advance paves the way for one day fixing mutations in mitochondria. Those energy-producing organelles are inherited from a mother and have their own DNA, distinct from the genetic information — from both parents — that’s stored in a cell’s nucleus.

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"Mutations in mitochondrial DNA cause over 150 distinct syndromes and affect 1,000 to 4,000 children born in the United States each year. There are no cures for these diseases and currently, the only way to prevent a child from inheriting dysfunctional mitochondria is a controversial “three-parent baby” method (SN: 12/14/16). This in vitro fertilization technique requires mitochondria from a donor egg, in addition to genetic information from a mother and father.

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"The toxin secreted by the bacteria Burkholderia cenocepacia unexpectedly proved to be the solution needed to create a mitochondria-friendly base editor. Marcos de Moraes, a microbiologist at the University of Washington in Seattle, deduced that the toxin killed bacteria by causing disruptive DNA mutations. But for months, he couldn’t untangle how the process worked at a molecular level. He was on the verge of moving on from the project when a single late-night experiment made everything fall into place.

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"The new cytosine-converting enzyme, however, was as lethal to mammalian cells as it was to bacterial prey. The first step in “taming the beast” was modifying the toxin so it didn’t just indiscriminately mess up double-stranded DNA, Liu says. The researchers split the protein into nontoxic halves; the two pieces changed cytosine to thymine only when they were brought together to the same spot of DNA.

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"To direct the enzyme halves’ activity, the researchers attached TALE proteins, short pieces of protein that could be chosen to target specific stretches of DNA. In cell culture experiments, the mitochondrial editor successfully converted cytosine to thymine at intended mitochondrial DNA locations, with efficiencies ranging from 5 to 49 percent.

"Future work will aim to improve efficiency, develop new types of mitochondrial editors that can produce other DNA base changes, and see if mitochondrial gene editing works in animals.

“'This is just the first step,” says Shoukhrat Mitalipov, a mitochondrial biologist at the Oregon Health & Science University in Portland who was not involved in the work. “But in the right direction.'”

Comment: Thank goodness for our brilliant brain which can solve problems caused by molecular mistakes (bad mutations) in DNA. It is logical to hypothesize that God knew there would be molecular errors that we might be able to correct. I imagine dhw will again crow over these admissions that living mechanisms make mistakes. It is the reality we have to experience.