I disagree...
When you say "RNA" naturally evolved... what evidenced do you have that it was natural? Who told RNA to develop a DNA? When was the first time that it happened? Or was it purpose driven! Just because a person said "it was natural" doesn't mean that it was.
I like the way these people said it!
Not having every answer doesn't mean Allah created people. Or Zeus. Or Yahweh. But evidence we do have. More is coming. Every year the gap is closing. Religious folks can disagree as much as they want. The truth isn't impacted by that.
There are over 10,000 children deaths every day from starvation. Every day. Suffering on these large scales shows there is no theism. Probabilities with illness rates playing out exactly as predicted show no deity is healing people.
Science denial in the name of a deity always ends up being wrong. Doing science with a result in mind is the worst way to find truth.
We don't know. We are starting to get a picture of early life. Self replicating chemicals, peptides, amino acids, have been demonstrated, DNA coming from simpler RNA has evidence.
RNA evolving also has evidence. More will be found.
Evidence for RNA origins
www.nature.com
The RNA-world hypothesis proposes that today's DNA-based life forms evolved from earlier ones that were based on much simpler RNA molecules...
biochemist Michael Yarus marshals the theoretical considerations and lab experiments that lend support to this notion for the origin of life.
Chemists Stanley Miller and Harold Urey tested this at the University of Chicago in 1952 in their 'primordial soup experiments' that created amino acids from methane, ammonia, hydrogen and water when the mixture was exposed to an electrical discharge.
Other recent discoveries have revealed the existence of small RNAs, including microRNAs, that are intimately involved in controlling gene expression and translating messenger RNA. But the fact that RNA can adopt this vast catalogue of forms is insufficient evidence for a precursor RNA world.
More compelling is the ability of RNA to evolve under selection pressure, as demonstrated in the elegant SELEX experiments done in Larry Gold's lab at the University of Colorado, Boulder. This evolutionary adaptability may be why it is the nucleic acid of choice for the genome of some of the most difficult and changeable pathogens, such as the influenza viruses. It is a key part of the argument that it was RNA that generated subsequent life forms, and that RNAs were a primitive system for making short chains of amino acids — a system that evolved to produce the protein-based structural and metabolic machinery found in organisms today.
Further proof for the primitive RNA world could come from next-generation sequencing platforms that allow deep sampling of nucleic-acid populations from microorganisms in exotic locations, such as in deep-sea volcanic vents.
The Origins of the RNA World
The general notion of an “RNA World” is that, in the early development of life on the Earth, genetic continuity was assured by the replication of RNA and genetically encoded proteins were not involved as catalysts. There is now strong ...
www.ncbi.nlm.nih.gov
There is now strong evidence indicating that an RNA World did indeed exist on the early Earth. The smoking gun is seen in the structure of the contemporary ribosome (
Ban et al. 2000;
Wimberly et al. 2000;
Yusupov et al. 2001). The active site for peptide-bond formation lies deep within a central core of RNA, whereas proteins decorate the outside of this RNA core and insert narrow fingers into it. No amino acid side chain comes within 18 Å of the active site (
Nissen et al. 2000). Clearly, the ribosome is a ribozyme (
Steitz and Moore 2003), and it is hard to avoid the conclusion that, as suggested by Crick, “the primitive ribosome could have been made entirely of RNA” (1968).
Researchers may have taken the first step toward solving this mystery. They’ve shown that RNA molecules can grow short proteins called peptides all by themselves—no ribosome required. What’s more, this chemistry works under conditions likely present on early Earth.
“It’s an important advance,” says Claudia Bonfio, an origin of life chemist at the University of Strasbourg who was not involved in the work. The study, she says, provides scientists a new way of thinking about how peptides were built.
But to give rise to modern life, RNA would have had to somehow “learn” to make proteins, and eventually ribosomes.
Now, Carell’s team reports that a pair of noncanonical RNA bases can do just that. They started with pairs of RNA strands, each made up of strings of RNA bases linked together in a chain. These pairs of strands were complementary, enabling them to recognize and bind to each other. At one end of the first strand—called the “donor” strand—they included a noncanonical RNA base, called a t6A, which is able to bind an amino acid. On the end of the second RNA strand—called the “acceptor” strand—they added another noncanonical RNA base, called mnm5U.
Carell’s team found that when the complementary donor and acceptor RNA strands bound together, the mnm5U grabbed ahold of the amino acid on the t6A. With the addition of just a bit of heat, t6A let go and passed its amino acid over to mnm5U, and the complementary strands disassociated and drifted apart.
But the process could repeat. A second donor strand carrying another amino acid could then bind to the acceptor strand, and pass over its amino acid, which was linked to the first.
The process could create peptide chains up to 15 amino acids long, the team reports today in
Nature.
Now, Carell’s team reports that a pair of noncanonical RNA bases can do just that. They started with pairs of RNA strands, each made up of strings of RNA bases linked together in a chain. These pairs of strands were complementary, enabling them to recognize and bind to each other. At one end of the first strand—called the “donor” strand—they included a noncanonical RNA base, called a t6A, which is able to bind an amino acid. On the end of the second RNA strand—called the “acceptor” strand—they added another noncanonical RNA base, called mnm5U.
Carell’s team found that when the complementary donor and acceptor RNA strands bound together, the mnm5U grabbed ahold of the amino acid on the t6A. With the addition of just a bit of heat, t6A let go and passed its amino acid over to mnm5U, and the complementary strands disassociated and drifted apart.
But the process could repeat. A second donor strand carrying another amino acid could then bind to the acceptor strand, and pass over its amino acid, which was linked to the first.
The process could create peptide chains up to 15 amino acids long, the team reports today in
Nature.
The design of self-replicating helical peptides
Abstract
The self-assembly of helical peptides and information transfer through autocatalysis and cross-catalysis are the foundation of peptide-based
molecular evolution models. Many fundamental properties of living systems, such as environmental sensitivity, chiroselectivity, cross-catalysis, dynamic error correction and conditional selection, are exhibited by various self-replicating peptide systems. Recently, advances have been made in the design of peptide systems with autocatalytic and cross-catalytic properties.
