This man-made cell has the smallest genome ever — but a third of its genes are a mystery


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This man-made cell has the smallest genome ever — but a third of its genes are a mystery

washingtonpost.com/news/speaking-of-science/wp/2016/03/24/the-creators-of-the-first-synthetic-life-made-a-cell-with-just-enough-genes-to-survive/ .

The news is from J. Craig Venter Institute. They had previously been known for putting together a synthetic combination of DNA which survived in a cell and was capable of reproduction.

science.sciencemag.org/content/329/5987/52 .

DNA is the molecule that forms our genes. These are used for coding proteins, which do the work of our cells. Cells are the basic unit of biology. DNA is also needed for reproduction, to pass the information to offspring. Humans have trillions of cells, and most of them contain their own set of DNA. Some organisms, like bacteria, have only one cell, but still need DNA to make protein and for reproduction. You have probably seen, but if you want you can see in the picture in the link below, DNA looks like a twisted ladder. Each step of the ladder has a smaller molecule that acts, in sequence with the other steps, as a code for the protein so it can be made correctly. There are 4 types of steps which are called bases and in bacteria it takes about 1000 bases per gene. And as the WP article points out, “to build a DNA code that will support life, you need to be pretty much error-free.”

Picture from NIH, National Human Genome Research Institute, Talking Glossary, Double Helix: The link is (you have to hit the illustration button for the picture):

genome.gov/Glossary/index.cfm?id=53 .

Scientists have been trying to determine what is the least number of genes a single cell, such as a bacterium, can have and still stay alive. They had thought it would be in the vicinity of 250, but have found, at least in this approach, that more genes are needed than they thought. They came up with 473. (There are 32% they don’t know their function.) This means that close to half a million bases in exact order is the minimal amount for an organism to function.

An abstract of the new scientific paper is here:

science.sciencemag.org/content/351/6280/aad6253 .

What are the chances that even half of that, an exact sequence of 250,000 bases, could have randomly come together to start life, composing a complete genome which codes for life processes including transfer of light energy to sugar, breakdown of that sugar to make the structures of the proteins, reproduction and other functions, and organize all of it in tiny cells? This could not have happened by chance even in billions of years.

Praise God for His Creation.


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The first man-made cell is a misnomer. Material was inserted into an existing cell. The probability for the ever-increasing complexity of cell function argues against chance formation. By 'ever increasing," I refer first to “junk DNA” which was decided at the time to be leftover material from the past or just remnants that just did nothing but were carried along anyway. That has been proven to be incorrect. Junk, or non-coding DNA, does have function. The next discovery was a second code written on top of the existing DNA code scientists already knew about. This multiplies, by orders of magnitude, the complexity of our DNA. Far beyond chance assembly and organization.

Ed


#3

First of all, is there some reason you think that early life would have used DNA? That’s certainly not the view of researchers these days.

Second of all, none of this happened in one step, so at the very core of your argument is a strawman, as there always is with the watchmaker argument.


#4

I’ve read the research. Scientists are just guessing. All that’s happening here is getting a parts/functions list.

Ed


#5

Thanks for the clarification.


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Before you have a living cell, molecules obey the laws of chemistry, not mutation and selection. The RNA self-replicators, made in the lab, have dozens of bases that have to be in nearly necessary order of their sequence, one absolutely conserved, just to combine. Besides this, you would have to explain how RNA eventually turned into DNA as the main coding molecule.

These RNA replicators would need the right backbone–ribose and phosphate. Ribose is made in the cell, not in non-living nature, so you need a biological system to make it, but the cell needs 473 genes to do its collective work, including making ribose. The energy to put the RNA and DNA molecules together comes from a molecule called ATP. This is made from conversion of the sun’s energy to hydrogen protons, which then serve as an electrochemical gradient to go through the biological machine of ATP synthase (ATP sin-thase) which sits on a necessary membrane. To see the mechanism, you can go to the video (about 4 minutes) in my blog at the link here:

womanatwell.blogspot.com/2013/01/microbiology.html .

I encourage you to read the whole post, because it shows not only ATP synthase but just a few of the other molecules that are needed for the machinery to work, and the makeup of just one part of one machine, which would take hundreds of bases to code so that the protein part is the right shape and chemical makeup to do its job. The ATP synthase system has been called “evolutionary old” because frankly it was needed from the start of life.

RNA self-replicators don’t “know” they are supposed to select for life, and therefore, even ignoring the rest of the biological necessities, they would have to search for useful strings under the Law of Mass Action of chemistry, which is probabilistic. In order to have natural selection, you need something useful from which to select.


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