As I have noted in other posts, I greatly admire Deb and Dee over at The Wartburg Watch (TWW) because they are good examples of thoughtful Christians. Among many things, Deb and Dee are pro-science and are concerned at the level of ignorance in conservative communities.
One of the pet peeves is the fear and ignorance surrounding the theory of evolution. I am thinking about writing a column for them and here that will be themed “Explaining Biological Processes using proper unscientific English.
First, I will introduce a concept.
Next, I will explain the process using unscientific English but I will also introduce the reader to some vocab with simple explanations.
Finally, I will put the concept into context within which the concept becomes of some significance to most people
Here is an example of DNA replication and how homologous genes supports evolution.
I am a Biologist
I am also a Christian
I also firmly believe that life evolved from common ancestry.
I need to refresh myself with respect to Venema’s writings but based upon what Lyn wrote, it looks like he has focused on molecular genetics particularly the sameness of the genome of different species.
The same-ness of the DNA between species is called homology.
Things that are shared by almost everything is called deep homology.
Another term you will see is “conserved.”
Everything uses DNA or RNA to encode its information in order for it to be passed down to the next generation. Almost everything uses DNA to pass the directions onto the next generation Almost everything transcribes RNA from a template of DNA when it is time to make something the organism needs (protein) The only exception is retroviruses (Like HIV) that uses an enzyme called reverse transcriptase to use RNA to make DNA to insert into the host DNA (likely losing people here so I’ll stop.)
So almost everything uses DNA to pass traits to the next generation
The DNA is the same no exceptions. (How amazing is that!)
The way DNA works is base-pairing (that is why the code is accurately passed on and on and on with very few mutations.)
There are four bases in DNA no more, no less. They have a complimentary base they always base pair with one another. A, T, G, C.
A is always with T
G is always with C
There are a lot of molecules that are similar to these (Look at adenine and caffeine and chocolate which is theobromine and they are almost the same but only these four bases are used.) Why? Why is this? It points to everything coming from a common ancestor that gave rise to what we have today via natural selection.
If I am helping, I’ll do another post (explaining the insulin and transcription and translation and codons but lets see, if I’m blabbering at bedtime and doing no good, I’ll just fade into the woodwork.
Next, I discuss transcription and translation using simple words.
Here you go
Transcription and translation simplified.
DNA is a long chain of bases that base-pair to form the famous double helix. It opens up and each half is used as a template during replication.
That is how instructions (everything an organism will need) is passed onto the next generation.
That is DNA’s first job.
DNA has a second job and that is to provide a template to be used to transcribe a stretch of DNA needed to make a protein. That stretch of DNA is called a gene. When the organism is ready to make protein, it needs instructions because all proteins are a long chain of building blocks called amino acids. There are twenty essential amino acids.
This is a bit complicated.
DNA is a very old molecule that, in organisms more complicated than bacteria, (eukaryotes) live in the nucleus and is protected there so it will survive.
RNA, on the other hand, isn’t expected to live longer than it needs to finish the job of making a protein.
DNA provides the template to translate the gene that is found on DNA into RNA and the RNA gets taken out of the nucleus to the cell to help make protein.
A special molecular machine called a ribosome actually does the hard work of putting the amino acids together in the correct order (which is critically important because one mistake can kill a new baby.) The RNA tells the ribosome what the correct order is. RNA does this by the order in which the bases are found on that gene. Because there are twenty amino acids and you need a start code and a stop code, you need three bases for each amino acid or stop or start. If there were only fourteen amino acids instead of twenty, we could have squeeked by with two bases for each amino acid.)
Because we have a triplicate code, there are 64 possible combinations which means there are several codes for some of the amino acids. http://barleyworld.org/sites/default/files/figure-09-08_1.jpg
Almost forgot, one difference between DNA and RNA is in RNA, the T is substituted with U. (there are reasons beyond scope.)
So, you could build an insulin protein using many combinations of triplicate codes but only the same ones are found across a diverse cohort of organisms.
This also supports common ancestry
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