a poke in the eye of creationist fiction

Exhibition of human origins shows all creatures closely related

Can you imagine that mice share 95 percent of human genes, fruit flies share 36 percent, and plants about 18 percent? Even comparing any two persons, regardless of what they look like, their DNA differ by an average of 0.1 percent.

An exhibition of human origins about to open at the American Museum of Natural History will show that all creatures on this planet are closely related, having a common ancestor from more than 3 billion years ago.

Among the human being's closest relatives, the DNA of chimpanzees and bonobos, until recently known as the pygmy chimpanzee, are 98.8 percent identical to ours.

The three primates are descended from a single ancestor species that lived 6 or 7 million years ago.

How can so much of a chimpanzee's genome be similar to a human's when they look and act so differently?

Rob DeSalle, a molecular biologist at the Institute for Comparative Genomics of the museum, said "the answer lies where that 1.2 percent difference is. Most scientists suggest that the differences are in regions of genes that control how they are expressed."

"They can turn genes on and off and regulate the amount of matter made from the genes, much as a faucet can regulate the amount of water going into your bathtub. Because gene products are critical to how different structures in the body are made, the different regulation of gene products in chimpanzees can produce the differences we see between humans and chimpanzees," DeSalle told Xinhua in a press preview tour on Tuesday.

Each human cell contains roughly 3 billion base pairs, or bits of information. Just 1.2 percent of that equals about 35 million differences.

The exhibition combines, for the first time in a major show of its kind, a wealth of mutually reinforcing evidence from two seemingly disparate fields of science -- fossil records and genomic data -- to present a sweeping and comprehensive story of human origin and evolution.

Entering the hall, visitors are greeted by an arresting gateway icon: the skeletons of a chimpanzee, a reconstructed Neanderthal, and a modern human, posed against an eye-catching animated backdrop showing cells, chromosomes, and three-dimensional bone scans of the human being and our close relatives.

The fossil and genomic evidence reinforce and complement each other as the visitors walk through the hall.

On the right, visitors are introduced to the tools and concepts used by paleontologists to study the rich fossil history of our species. Near the fossils of extinct early primates, they encountered a cast of an historic Neanderthal skullcap discovered by miners.

On the left side of the section, visitors learn how scientists extract and study the DNA from humans and closely related primate species to piece together the complex history of human evolution.

A vial of extremely precious 40,000-year-old Neanderthal DNA is on public display here for the first time, donated by the Max Planck Institute in Munich, the first laboratory in the world to have successfully extracted this elusive genetic material.

The skeleton of the famous "Lucy" that was found by paleontologists Donald Johansen and Tom Gray in Hadar, Ethiopia, in 1974, is showcased in the middle of the hall.

"Lucy" lived in eastern Africa some 3.2 million years ago. Members of her species, Australopithecas afarensis, ventured down from the trees and into the grassy woodlands where they walked on two limbs instead of four. She had a chimpanzee-size brain but human-like tooth patterns.

She was named "Lucy" after the Beatles' song "Lucy in the Sky with Diamonds."

By comparing DNA sequences from humans living across the world today, researchers have learned that modern humans first migrated from Africa into Asia and Australia about 60,000 years ago.

The research was based on the unchanged part of the human DNA. Every human inherits half of his or her DNA from their mother and half from their father. The DNA is recombined or shuffled, except two chunks of DNA -- mitochondria DNA and the Y chromosome.

The permanent exhibition also explores what sets humans apart from other species, such as artistic creativity, language development, and tool use, while also speculating about the future of our species.

There are videos presenting some amazing behavior of birds, dolphins, monkeys and other animals that resemble a human capacity for creating language, tools, music and art. All hint at some type of intelligence but fall short of what we think of as human.

A child-friendly interactive demonstration explores the "language" capabilities of one of our closest animal relatives, the bonobo ape. A touch-screen display presents some of the research from the Great Ape Trust of Iowa, where bonobos are taught how to communicate with humans and other primates using a specially designed pictogram keyboard.

Full language probably originated at some point before about 50,000 years ago. Humans can express abstract thought through languages while other creatures cannot. It is our intelligence that makes us different. None of the other animals make paintings or sculptures, or play music.

The brain wiring that permits complex thought has been acquired along with all the other striking physical features of our species. It must have been a cultural rather than a physical innovation that sparked abstract thought in some population of the homo sapiens species.

With regard to our future, the exhibition cautions against changing human genes artificially.

"All humans need to be aware of the changes that can be made and of how they might affect human evolution," DeSalle said.

Since humans can change the environment in drastic ways, the exhibition appeals to visitors to be aware of our environment because it is vital to our survival and suggests that human survival depends on the potential of our species to adapt to a changing environment.

According to the museum, the exhibition in the Anne and Bernard Spitzer Hall of Human Origins, which will open to the public on Feb. 10 is the combined effort of some 300 scientists and presents some of the latest and most exciting discoveries in the world.

The American Museum of Natural History was established in 1869, two years before the publication of The Descent of Man by Charles Darwin.

For well over a century, the museum has been a leader in phylogenetics, examining a diversity of species that represent critical branches in the pattern of relationships often depicted as the Tree of Life, and in studying patterns of evolutionary change over the past 3.5 million years.