European Stars and Stripes (Newspaper) - June 29, 1990, Darmstadt, Hesse                                Biologists redraw life a family tree i by Susan okie Washington Post m jul Ore than 2,300 years after Aristotle a my divided iving things into Plant and animal j hmm i kingdoms and More than a Century after 1i Charles Darwin first proposed that All species evolved fro Rrt a common ancestor scientists in one of the youngest branches of biology Are radically redrawing life a family tree. The revisions Are emerging from the new ability of molecular biologists to compare genes from All kinds of creatures and find the mutations that dictate evolutionary change. That approach is supplanting the old method of comparing Gross Anatomy. Among the discoveries that biologists consider to be startling insights $ the old division of humans and apes into two i families makes Little evolutionary sense. According to the genes it would be More logical to put humans chimps and gorillas in one evolutionary group quite separate from other apes such As i orangutans and Gibbons. Within that group chimpanzees Are More closely related to human beings than they Are to gorillas. A bacteria Long grouped into a single Quot kingdom a Are actually made up of at least two fundamentally different forms of life. Some bacteria it turns out Are More different from each another at the genetic level than a human is from an Oak tree. T the single celled life forms known As protists which include the protozoa Are much More ancient and diverse than previously thought. Some like an intestinal parasite called Guardia May have appeared More than 3 billion years ago and May be a Quot missing link Quot Between bacteria and More advanced life forms. A evolution has occurred not Only through the gradual accumulation of mutations in a cells Dan but at times through the merging of the genes of two unrelated creatures to create a new kind of organism. Humans Are the descendants of such a new organism. A the worlds 11 species of crocodiles found in widely separated regions around the Globe Are so closely related that scientists now think they May have evolved from a common ancestor in a single location As recently As 12 million years ago. This implies that crocodiles were evolving vigorously Long after the Quot age of reptiles Quot closed 66 million years ago and that they must have swum across the oceans to reach their current habitats. Such findings have Quot led to a fundamentally different View of the world of living things said Mitchell Sogin an evolutionary biologist at the Marine biological Laboratory in Woods Hole mass. Since 1980, when the University of Michigan established the first Laboratory devoted to deciphering genes to study evolution the Field has grown rapidly. It has revolutionized a Branch of science that for decades was the province of anatomists and palaeontologists peering at fossils and preserved animals in the Back rooms of museums. Quot its really booming. It s incredible Quot said Michael Braun chief of the smithsonian institution s new Laboratory of molecular systematics. A at meetings this past year there s been a 300 percent increase in papers Over three four years  traditional evolution research proceeded by identifying anatomical traits shared by different species of living things a the shapes of Bones for example or the Structure of Flowers. The More similar the forms the More closely related the species were presumed to be. The new molecular approach compares More fundamental characteristics the genetic signals that determine the anatomical differences. In principle comparing genes is like comparing sentences of English. Both English and the genetic language Are written As a sequence of units a the 26 letters of English and the four molecules that make up genes often designated at g and c. The letters of the genetic alphabet Are the initials of the molecules names. Each Gene can be represented As a specific sequence of these four letters called bases. Most genes Are hundreds or thousands of bases Long. Evolution occurs when a genes sequence of bases is altered a usually As the result of an error when the genes Are being duplicated for cell division a and the altercation causes a change in the Gene s portion of the blueprint that dictates the organisms form and behaviour. As the number of mutations accumulates in a subgroup of some species the organisms become less closely related to their Parent Stock. The More changes in sequence the More distantly related the species. For instance the full set of human genes contains about 6 billion bases. When genes from one human being Are compared to genes with the same function from any other person the sequences average about 99.8 percent identical. That Small difference averaging Only 1 in every 500 bases is enough to produce All the individual variation in the human species. When a Given human Gene is compared to an equivalent Gene from another species there is less similarity in their sequences. Comparisons of Many species have shown that the More distantly related any two species Are the less similar Are their equivalent genes. In most cases genetic comparisons agree Well with the evolutionary relationships that generations of biologists have inferred from Gross Anatomy. But the genetic method is now generally accepted As so much More precise and so much More widely applicable a it can be used to compare species that have no equivalent organs or structures it is becoming the Standard for determining evolutionary relationships. Genes can be used to study evolutionary relationships even among creatures that seem to have nothing in common but life itself. For instance the Gene that contains the blueprint for the ribosome a Basic piece of cellular machinery is found in All cells. Comparing differences in the sequences of ribosome genes has allowed researchers to measure genetic relatedness among All classes of living organisms from bacteria to human beings and to use such measurements to construct Quot Trees Quot of life that show which groups must have evolved from common ancestors. Much of the Boom can be traced to the invention a few years ago of a new technology called polymerase Chain reaction or per. It allows researchers to take a single copy of any Gene a including one taken from a Long dead Plant or animal a and make thousands of copies in a few hours. Since Many copies of a Gene Are needed for analysis per makes it possible to Analyse genes in scarce Supply. How Many kingdoms in the world of life origin of use pro test 1 Protist 2 fungi that non specialists often Lump Earth s life forms into two kingdoms plants and animals. For Many years biologists have recognized five plants animals Monera including bacteria and Blue Green algae fungi and protists which includes protozoans. Now Dan studies suggest there Are at least two kingdoms of bacteria and four of protists. Compared to bacteria and two Protist groups plants and animals Are newcomers. Protist 3 y 4.2 3.0 billions i of years ago 2.0 1.0 now Washington Post 2 a new View of anthropoid Gibbon hominids old View new View in the old View human beings hominids were classified As a Miffy separate from the ape family Pong ids. In the new View humans chimpanzees and gorillas cons Titu family and the other apes orangutans and Gibbons Are in a different family