Evidence for pre-planning; humans and yeast (Introduction)

by David Turell , Wednesday, May 27, 2015, 18:04 (3250 days ago) @ David Turell

50% of human genes used in yeast work!-http://www.the-scientist.com/?articles.view/articleNo/43043/title/Human-Genes-Can-Save-Yeast/-"A large number of human genes can substitute for their defective counterparts in yeast and prevent the microorganisms from dying, according to a paper published today (May 21) in Science. Of more than 400 human-to-yeast gene replacements performed, almost 50 percent were effective at compensating for a missing vital function.-"Bakers' yeast (Saccharomyces cerevisiae) shared a common ancestor with humans about a billion years ago. And this relationship, albeit distant, means that “when we read the DNA and look at their genomes we can recognize many equivalences,” said molecular biologist Edward Marcotte of the University of Texas at Austin who led the new study. “In fact, there are thousands of genes shared between humans and yeast.”-"These shared genes may appear similar, but Marcotte wanted to put them to the test, asking: “Are they swappable?” That is, could the gene encoding a human protein replace the corresponding gene in a yeast cell? Such experiments have been performed for a number of individual genes, but a large-scale, systematic approach had been lacking. “We wanted to test it for as many genes as we could feasibly do,” Marcotte said.-"The team chose test genes based on two criteria: that the yeast version of the gene was present in a single copy and that it served a function critical to cell survival. Using yeast strains in which these critical genes could be turned off at will, the team tested whether transfer of the equivalent, or orthologous, human gene could save the yeast from death.-"Forty-three percent of the 414 gene replacements the team performed could indeed rescue the yeasts' growth defects. Incorporating data from previously reported substitution experiments, that percentage rose to 47.-*****-"Abstract: To determine whether genes retain ancestral functions over a billion years of evolution and to identify principles of deep evolutionary divergence, we replaced 414 essential yeast genes with their human orthologs, assaying for complementation of lethal growth defects upon loss of the yeast genes. Nearly half (47%) of the yeast genes could be successfully humanized. Sequence similarity and expression only partly predicted replaceability. Instead, replaceability depended strongly on gene modules: Genes in the same process tended to be similarly replaceable (e.g., sterol biosynthesis) or not (e.g., DNA replication initiation). Simulations confirmed that selection for specific function can maintain replaceability despite extensive sequence divergence. Critical ancestral functions of many essential genes are thus retained in a pathway-specific manner, resilient to drift in sequences, splicing, and protein interfaces. (paywall) - A.H. Kachroo et al., “Systematic humanization of yeast genes reveals conserved functions and genetic modularity,” Science, 348:921-25, 2015."-Looks like pattern pre-planning to me, as previously discussed, as well as evidence that some type of evolutionary design controls are in place. Hard to deny evolution as a process with this kind of evidence, but it sure smells of Theistic guidance.