What about the DNA evidence for evolution?

Facts:

• DNA from monkeys and humans is similar
• Human DNA contains mutations which are similar to monkey DNA mutations

Quotes:

• So God created man in his own image, in the image of God created he him; male and female created he them. Gen 1:27
• And God saw everything that he had made, and, behold, it was very good. And the evening and the morning were the sixth day. Gen 1:31

Suggested response:

What is the evidence?

Two arguments that use DNA evidence to support evolution are as follows:

1. Monkey and human DNA is 98% the same. This proves they must share a common ancestor.
2. Human DNA contains many mistakes. These mistakes are shared by monkeys, again proving a common ancestor. Since a Creator would not make mistakes, while evolution works through mistakes, the later must be true.

DNA similarities

DNA similarities between humans and chimpanzees have been reported for several decades. Quoted similarities include 98.77% ⁽¹⁾The Chimpanzee Sequencing and Analysis Consortium,Initial sequence of the chimpanzee genome and comparison with the human genome; Nature Volume437, 1 September 2005, doi:10.1038/nature04072., 95% ⁽²⁾Britten RJ, Divergence between samples of chimpanzee and human DNA sequences is 5%, counting indels, PNAS Volume 99, 15 October 2002 no. 21 pgs 13633–13635. and 67% ⁽³⁾Cheng Z et al. A genome-wide comparison of recent chimpanzee and human segmental duplications, Nature Volume 437, 1 September 2005, doi:10.1038/nature04000., depending on which type of genetic variation is being measured. DNA is a complex biological chemical with many roles. The function of DNA can be assessed in many different ways and this is why different estimates have been made. As we come to understand more about DNA and its function, these estimates will no doubt continue to change.

Irrespective of how DNA similarities are measured, it is true that there are similarities between the DNA of humans and chimpanzees. These similarities can be interpreted in a number of ways.

A common ancestor

It is argued that DNA similarity between species is consistent with these species having a common ancestor. This scenario is true of siblings within a family – they share 50% of their DNA and have the same parents. But is it necessarily true that all organisms sharing common sequences of DNA must have a same ancestor?

DNA forms the blue print of life and is a chemical code describing the building blocks of life and how they are to be assembled. Species living in similar environments, with similar biological functions and made from similar building blocks are likely to have similar DNA sequences. Similarities in DNA sequences are simply measures of similarity between species. Concluding that a common ancestor is required is not logically necessary, and is an interpretation of an observation rather than a proof of evolution.

DNA mistakes

It has also been argued that DNA mistakes or mutationsare abundant,giving support to the idea that life has evolved through random processes. By contrast, if life was created by a perfect being, we would expect no mistakes in His handiwork.

One example of this argument is a gene involved in Vitamin C synthesis (called X GULO). This gene is observed in many species, but there are a few exceptions where it appears to have been ‘inactivated’ by mutations. Species such as the chimpanzee, gorillas and humans have an inactivated gene (and share the same mutations) which is not translated into a working protein. This means they are unable to produce their own supply of Vitamin C – it needs to be ingested.

In the past, DNA was only considered functional if it was translated into protein. This meant that the 98.5% of DNA, which is not translated into protein, was called ‘junk DNA’. It is now thought that 80% of the genome has a function, even if it is not translated into proteins ⁽⁴⁾Bernstein BE et al. An integrated encyclopedia of DNA elements in the human genome,NatureVolume 489,September 2012 doi:10.1038/nature11247.. There are also suggestions of an advantage for humans in not producing their own Vitamin C internally, but relying on their food as the source ⁽⁵⁾Grano, A. & De Tullio, M. C. Ascorbic acid as a sensor of oxidative stress and a regulator of gene expression: The Yin and Yang of Vitamin C. Med Hypoth69, 953–954 (2007). ⁽⁶⁾Halliwell, B. Vitamin C and genomic stability. Mutat Res 475, 29–35 (2001).. This example of a DNA mistake may not be a mistake after all. Human knowledge is incomplete and it is a mistake to conclude that no known purpose is the same as no purpose at all ⁽⁷⁾This type of argument has long been used to support evolution. An example of how time overturns these argument is the list of 86 vestigial human organspublished by Robert Wiedersheim in 1893. Today, all of these organs have a known function..

Of course, it is possible that there are mistakes in our DNA and in other parts of creation. Genesis describes God creating the world ‘very good’ but this state has not been maintained (Gen 1:31). Decay is at work and is evident around us (Rom. 8:20-22). Are the mistakes we observe evidence of creation in decay, or are they evidence of evolution in action? It is difficult to believe that an accumulation of random errors can drive a process responsible for all life on earth.

This matters because:

DNA evidence for evolution is not as convincing as it is made out to be.

Further sources:

Jon Cohen, Relative Differences: The Myth of 1%,Science, Volume 316:1836, June 29, 2007.