Yeast can survive on human genes

A new study shows that although yeast and human have evolved along different paths for 1 billion years, there are still strong family resemblances between them The researchers found that after inserting more than 400 human genes into yeast cells at one time, almost 50% of the genes were able to function and keep the fungus alive "It's amazing," said Matthew Hahn, an evolutionary biologist at Indiana University in Bloomington, who was not involved in the study "This means that similar genes can still perform similar functions one billion years after isolation," he said For years, scientists have known that humans share similar molecules with microbes that help us make bread and beer The human genome contains one third of yeast gene copies On average, the amino acid sequences of comparable yeast and human proteins overlap by 32% An example of shared genes has intrigued Edward Marcotte, a systems biologist at the University of Texas at Austin, and colleagues Yeast are single-cell and bloodless, but their genes can coordinate the growth of new blood vessels in vertebrates In yeast, these genes help cells respond to stress "This makes us question the extent to which yeast and human genes do the same job," said Marcotte To find out, Marcotte and his team decided to systematically examine whether human genes work in yeast The researchers selected 414 genes essential for fungal survival, such as those that help control metabolism and dispose of cell waste They then inserted a human version of each gene into yeast cells, and copies of the genes themselves were lowered, turned off, or removed The researchers speculate that if these yeast cells can grow in a culture dish, it means that human genes can fill the gap in their yeast equivalents The researchers found that 176 human genes enable yeast to survive in the absence of a vital gene "About half of these genes are interchangeable between humans and yeast and remain functional." "It perfectly illustrates the common heritage of living things," said Marcotte Next, Marcotte and colleagues analyzed the differences between replaceable genes The researchers assessed more than 100 possible effects, from the length of the gene to its protein abundance The similarity of DNA does not necessarily indicate whether a human gene can replace a yeast gene, Marcotte and colleagues reported in the online edition of science In fact, researchers have found that when a group of genes work closely together, most of them are replaceable or most of them are not For example, regulating every gene in the DNA replication pathway is irreplaceable, but almost all genes in the human cholesterol molecular pathway can be exchanged Bernard dujon, a molecular geneticist at the Pasteur Institute in Paris, France, said I was impressed by the "huge amount of work" put in by the researchers While the results of the study are not surprising, "I'm glad someone did it," he said Eugene Koonin, an evolutionary biologist at the National Center for Biotechnology Information in Bethesda, Maryland, warned that the team could only show that yeast with human genes can survive, but not that they are energetic enough to compete with unchanging strains Nevertheless, the study strongly supports the theory that comparable genes in different organisms have similar functions - which some researchers question, Koonin said Marcotte said the findings provide a way to further utilize yeast in research Scientists often study the former by embedding a single human gene into yeast cells But they can also transplant groups of interacting genes in order to make yeast more similar to human beings, which is very helpful for the study of new drugs or molecular pathways for the treatment of diseases.