We should also keep in mind that genes only specify what amino acids should be strung together to form protein molecules (or other polypeptides). In other words, the genes simply generate the molecular raw materials for the construction of bodies and body functions. It should not be surprising that the bodies of humans and chimpanzees are composed of roughly the same molecular ingredients. We exist in the same kinds of environments, and eat basically the same kinds of foods. So the similarity of genes and molecular ingredients does not rule out design. Designers of different kinds of automobiles make use of basically the same ingredients. In fact, the real problem is not the ingredients—the real problem is the arrangement of those ingredients into complex forms that work together to form a functioning machine. At a factory, the raw materials may arrive, in the form of steel, glass, rubber, plastic, etc. But the factory workers also need to shape and arrange those raw materials into an automobile. Similarly, genes may specify the formation of molecular raw materials, but it has not been shown that the genes specify exactly how those molecular raw materials are organized into the bodies of chimps or humans. Unless this can be shown, in some exact way, it is not unreasonable to attribute the similarity of chimp and human DNA, as well as the complex bodily forms of chimps and humans, to intelligent design.
The most recent research, as of the time of this writing, suggests that the human and chimpanzee genomes differ by as little as 1.5 percent (Travis 2000a). “What does that number mean? No one can say at the moment,” writes John Travis in Science news (2000a, p. 236). With so little difference, it is hard to explain many things—such as why the human brain is twice the size of the chimpanzee brain (Travis 2000a, p. 237). So the similarity of human and chimpanzee DNA is actually seen by many evolutionists as a significant problem that needs to be explained. Frans de Waal, a primatologist at Emory University, says, “Most of us find it hard to believe we differ by only 1.5 percent from an ape. It’s absolutely critical that we know what that 1.5 percent is doing” (Travis 2000a, p.
237). It appears that something more than DNA is necessary to put together the complex structures that define different species. That “something” more is arguably intelligent design.
Some scientists point out that the human chromosome 2 appears to be a combination of the chimpanzee chromosomes 12 and 13. They take this as evidence for evolution. But the fact that chromosomes may have been combined does not tell us how they were combined. It may have been part of an intelligently designed system for producing different bodily forms by systematic manipulation of the chromosomes. Other scientists point to the existence of “pseudogenes” as evidence for evolution. Pseudogenes are stretches of DNA that appear like genes, but do not function as genes. For example, the human DNA has a stretch of DNA that appears like a gene that in other animals produces vitamin C. But in humans it is not active. But the fact that a gene may have been deactivated does not tell us how it was deactivated. It could have been by the action of an intelligent designer.
African eve
Some scientists claim that genetic evidence shows all living humans can trace their ancestry to a female who lived in Africa about
200,000 years ago. Her descendants then spread throughout the world, replacing whatever hominids existed there, without interbreeding with them. The hominids they replaced would have been Neandertals or Neandertal-like descendants of Homo erectus, who supposedly left Africa in a previous wave of emigration between one and two million years ago.
Evidence from mitochondrial Dna
The above scenario is called the African Eve hypothesis, or the out-of-Africa replacement hypothesis. It was first announced in the
1980s by researchers such as Cann, Stoneking, and Vigilant, among others. Their conclusions were based on studies of mitochondrial DNA. Most of the DNA in human cells is found in the nucleus. This nuclear DNA is a combination of DNA from the mother and father. The sex cells of males and females contain half the DNA found in each parent. Thus when the father’s sperm combines with the mother’s egg, the fertilized egg of the offspring contains a full complement of DNA, different from that of either the father or the mother, in the nucleus. But the mother’s egg cell also contains small round compartments (outside the nucleus) called mitochondria, which are involved in the cellular energy production process.
The presence of mitochondria in eukaryotic cells is a bit of a mystery. In eukaryotic cells, the DNA is found on chromosomes isolated in the cell’s nucleus. In prokaryotic cells, there is no nucleus and the DNA molecules simply float in the cell’s cytoplasm. Almost all of the plants and animals living today are either single eukaryotic cells or are composed of many eukaryotic cells. Only bacteria and blue-green algae are prokaryotic. Evolutionists theorize that the mitochondria in today’s cells are remnants of prokaryotic cells that invaded primitive eukaryotic cells. If that were true, then this most probably happened very early in the evolutionary process, when only single celled creatures existed. This implies that the mitochondria in all living things should be quite similar. But the mitochondrial DNA in mammals “cannot generally be classified as either prokaryote-like or eukaryote-like.” Furthermore: “The mammalian mt [mitochondrial] genetic code is different from the so-called universal genetic code . . . mammalian mitochondria are very different from other mitochondria. In yeast mitochondria, for example, not only is there a slightly different genetic code, but also the genes are widely spaced and in a different order, and in some cases they contain intervening sequences. These radical differences make it difficult to draw conclusions regarding mitochondrial evolution” (Anderson et al. 1981, p. 464). In other words, the presence of the various kinds of mitochondria in different creatures argues against an evolutionary origin.
But let us now return to the main point. In mammals, the mitochondria in the mother’s egg have their own DNA. This mitochondrial DNA does not, however, combine with the DNA from the father. Therefore, all of us have in our cells mitochondria with DNA that came only from our mothers. The mitochondrial DNA in our mothers came from their mothers, and so on back into time. The African Eve researchers assume that the only changes in the mitochondrial DNA are the changes that accumulate by random mutations. By studying the rate of mutation, scientists believe they can use mitochondrial DNA as a kind of clock, relating numbers of mutations to numbers of years. And by looking at the mitochondrial DNA in different human populations in various parts of the world, scientists believe they can sort out which group is the parent group for the others.