According to an idea popular among young earth creationists, evolution cannot result in new genetic information, and biological information can only be degraded with time. There are variations on this theme, including the concept that mutations cannot be beneficial.
These statements are simply incorrect. Many of the arguments to support the “no new information” meme come from physics and engineering, and are usually supported by various interpretations of information theory. The problem is that none of the arguments have any biological validity, because they don’t take into account the facts of transmission and mutation of biological information. Some of these facts are as follows.
Biological information is stored, preserved, transmitted, and processed by the DNA of all living cells. The information is translated into specific protein structures that compose the cell’s phenotype (all its characteristics). While transmission of information can be subject to loss of accuracy in many physical systems, it isn’t in biology. Each step of the transmission process, including the replication of the DNA in the genome and its transcription into RNA followed by translation into protein structure, has a defined and extremely low error rate. This is not due to chance or luck, but to a complex and highly efficient set of repair systems that are constantly checking and fixing errors as they occur. While there is a small degree of error in DNA replication, this is not a burden but an advantage to cells, since it allows for mutation, variation and evolution.
The result of these repair processes is that there is no trend toward genetic or any other form of informational degradation with time.
Actually, evolutionary mechanisms also include a number of ways to increase and improve the quality of biological information. Among these are increases in gene numbers, the selection of mutations that increase the fitness of organisms, the development of extremely complex gene expression control networks that allow for rapid adaptation to environmental challenges, and the advantages of genetic recombination during sexual reproduction that produce novel combinations of alleles, leading to greater genetic diversity and more chances for survival.
Genes are often duplicated due to many factors including retrotransposon activity, replication errors, and environmental effects. A duplicated gene allows for a higher mutation rate than would usually be tolerated, since the duplicate is not necessary for the cell to survive. Sometimes, these highly mutated genes lose all function and become pseudogenes, but occasionally they become new genes with new functions.
The normal process of replication allows for some mutations to give rise to alternative alleles for specific genes, which may be detrimental, neutral or beneficial. Examples of new alleles that have arisen in the human population during the past 50,000 years of evolution include lighter skin for people who reside in dark sunless regions (allowing for a more efficient uptake of Vitamin D), the ability of adults to tolerate foods containing lactose (lactose intolerance is the biological norm past childhood), and resistance to a number of diseases.
There are thousands of examples of new beneficial genetic information that can be found throughout the world of plants and animals. The claim that mutation or time can only result in information loss is plainly false for biological systems, and such a claim has never been stated in the peer-reviewed recognized biological literature. Some who claim this idea to be true will quote valid, scientific papers, but they invariably either misunderstand or deliberately distort the actual statements or conclusions in the paper being quoted.