In another intriguing finding, the researchers identified a messenger RNA mRNA transcript from a gene on chromosome 2 that possibly may produce a protein unique to humans and chimps. Scientists have tentative evidence that the gene may be used to make a protein in the brain and the testes. The team also identified "hypervariable" regions in which genes contain variations that may lead to the production of altered proteins unique to humans.
The functions of the altered proteins are not known, and researchers emphasized that their findings still require "cautious evaluation. In October , the International Human Genome Sequencing Consortium published its scientific description of the finished human genome sequence in Nature. Detailed annotations and analyses have already been published for chromosomes 5, 6, 7, 9, 10, 13, 14, 16, 19, 20, 21, 22, X and Y.
Publications describing the remaining chromosomes are forthcoming. The sequence of chromosomes 2 and 4, as well as the rest of the human genome sequence, can be accessed through the following public databases: GenBank www. Michael C. Purdy, Washington University purdym wustl. To corroborate Darwin's theory, scientists would need to find a valid explanation for why a chromosome pair is missing in humans that is present in apes.
A fundamental part of the process by which science is done involves developing a testable prediction, also known as a hypothesis. Scientists offered two possible explanations for the discrepancy: Either the common ancestor had 24 pairs, and humans carry a fused chromosome; or the ancestor had 23 pairs, and apes carry a split chromosome. Their focused research led them to find a mutation on one human chromosome that explained what had happened.
In , a peer-reviewed scientific journal published results of the tests. It turns out that chromosome 2, which is unique to the human lineage of evolution, emerged as a result of the head-to-head fusion of two ancestral chromosomes that remain separate in other primates.
Three genetic indicators provide strong, if not conclusive, evidence of fusion. First, the banding or dye pattern of human chromosome 2 closely matches that of two separate chromosomes found in apes chimp chromosome 2 and an extra chromosome that does not match any other human chromosome. Second, a chromosome normally has one centromere, or central point at which a chromosome's two identical strands are joined.
Yet remnants of a second, presumably inactive centromere can be found on human chromosome 2. And third, whereas a normal chromosome has readily identifiable, repeating DNA sequences called telomeres at both ends, chromosome 2 also has telomere sequences not only at both ends but also in the middle.
Join us to receive the latest articles, podcasts, videos, and more, and help us show how science and faith work hand in hand. Does human genetic variation today provide evidence that we can trace our ancestry exclusively from a single couple? Biology, philosophy and religion work together to help us to understand the world we live in and to better know God. Part Three in the Uniquely unique mini-series.
We look to morality, language, and culture, and start to see that our species is quite an outlier. Author of "Thriving with Stone Age Minds," Justin Barrett responds to the reaction some people have to the idea of evolutionary psychology. Part Two in the Uniquely unique mini-series. When we look for what makes humans unique on this planet, looking at our biology is an obvious first step. The origins of human chromosome 2: a brief review Though I have discussed the evidence for a fusion event leading to human chromosome 2 before, perhaps a brief review of the evidence is in order.
Enter the Denisovans With that as background, we are now prepared to appreciate a new finding that comes from genomics work done on the Denisovan hominids, an archaic species that is more closely related to Neanderthals than to us, but that nonetheless interbred with some anatomically modern humans as they migrated out of Africa and populated the globe. What is BioLogos? Subscribe Now What is BioLogos? He holds a B. His research is focused on the genetics of pattern formation and signaling using the common fruit fly Drosophila melanogaster as a model organism.
Dennis is a gifted thinker and writer on matters of science and faith, but also an award-winning biology teacher—he won the College Biology Teaching Award from the National Association of Biology Teachers. He and his family enjoy numerous outdoor activities that the Canadian Pacific coast region has to offer. Podcast Episode. Article Advanced. By Stephen Schaffner. Featuring guests Dennis Venema and Michael L. By Justin Barrett.
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