Humans share kangaroos genes ― does this surprise anyone?
Science deals in figuring out the truth – a lot of truth. Truth is beautiful; therefore, science is inherently beautiful. Is it a small wonder that the modern civilization's foundation is anchored to scientific principles?
When we see the marvels of science, we are simply awed. On the macroscopic side, the tallest building stands erect majestically because the laws of physics, mechanics in particular, is used both by architects and builders to defy the gravitational pull of the earth; consequently, the Empire State Building, the Eifel Tower, and Taj Mahal could stand erect all these years. Microscopically speaking, the nucleotide sequence (read gene) homology between mouse and man also makes us wonder how these two species are interrelated!
When I read today (November 18, 2008) in the Net from a Reuter's science report in which it was mentioned that humans have a lot of kangaroo genes in their chromosomes, was I surprised? Not at all. Any student or person, who think Charles Darwin's scientific theory of evolution is the only logical explanation of origin of species, will surely admit that human beings have not evolved suddenly as the biblical account will lead us to belief ― based on a blind belief system.
As per Judeo-Christian belief, God created humans about 6,000 years ago. However, science is at odds with this figure. The Australian marsupial, kangaroo, had evolved about 150-170 million years ago. The blind belief systems of the world originating from Middle East would, however, lead you to believe that about 6,000 years ago all the species have evolved simultaneously. Therefore, all the fossil records have no meaning whatsoever as per the religious schools of thoughts.
Any reputable astrophysicists will however tell you that the age of the universe is about 5-6 billion years. This fact is at variance with the believers of any monotheistic religion such as Judaism, Christianity, and Islam. The religious scholars would propound that the earth is hardly 6,000 years old. Now, who is correct? Astrophysicists or the practitioners of the monotheistic religions? You be the judge.
Evolutionary biologists had estimated that the simplest life, prokaryotes, had evolved about 3.8 billion years ago. The process of photosynthesis through which simple energy rich compound such as hexose (sugar) could be made by sunlight and a bunch of enzymes (catalytic proteins) had evolved in water borne microbes such as cyanobacteria or photosynthetic bacteria about 3 billion years ago. It took about 1 billion years after the emergence of photosynthetic apparatus in bacteria for simple eukaryotes with mitochondria and chloroplast to have evolved. Again, it took one billion years to evolve complex multicellular organism. Therefore, about 1 billion years ago the complex eukaroytes were part of flora in waters.
The clock of evolution was running faster after the emergence of complex eukaryotes. In the next 500 million years fish and other chordates had populated the earth's streams, lakes, rivers, and oceans. About 475 million years ago the plants were evolving; thereby, populating the ground. About 400 million years ago, the insects and pre-gymnosperm (ancient seeded plants) made their way into our earth; thus making the world a bit crowded. About 350-360 million years ago the amphibians started to evolve while 50 million years later, roughly about 300 million years ago, the reptiles were making their way into our earth.
The last 200 million years saw the emergence of first marsupials such as kangaroos, opossums, bandicoots, etc., which lacks placenta – the vascular organ that develops in female mammals during pregnancy lining the uterine wall. From reptiles another line of animals – birds had evolved about 150 million years ago. On the plant side, the first batch of flowering plants started to grace our world about 130 million years ago. The land-based dinosaurs became extinct about 65 million years ago.
The first member of the genus Homo probably has evolved 2.5 million years ago. The first member of human that had some semblance of modern man had evolved about 0.2 million or 200,000 years ago. About 25,000 years ago, the last of the Neanderthal (ancestors of the modern man) ceased to exist. About 6,000 to 8,000 years ago, human being learned how to do the primitive agriculture probably somewhere in Mesopotamia (modern day Iraq and Southern Turkey ). The great religion, the first of the monotheistic class, Judaism, have evolved 2,500 years ago. In a nutshell, this is the history of the accent of modern human being.
On the contrary, the blind belief system would tell you that the earth is about 6,000 years old and all the life forms had evolved simultaneously. The scientists from early on wanted to know how the molecules of life for example amino acids (the building blocks of proteins and enzymes), nucleotides (the building blocks of DNA and RNA), etc., formed through abiogenesis (without inside the microbes or cells). The famous 'Miller-Urey' experiments of 1953 showed that under reducing environment, which is the absence of oxygen, a mixture of gas and electric spark could give rise to amino acids. This important experiment gave credence to the 'primordial Soup Theory' as propounded by J.B. S. Haldane and Aleksandr Oparin in 1920s.
I digressed a bit from the original theme of this article to give the readers a sense of how life forms have evolved over 3.5-3.8 billion years ago. The advent of genomics – the study of genome or the entire nucleotide sequence of an organism is a new branch of biology that dates back to hardly 3 decades. When I came to America in 1969 to study molecular biology, no one knew how to sequence the DNA or RNA. Dr. Sanger, a renowned British biochemist, however devised a method to sequence the primary structure of Insulin (a small protein) for which he received the Nobel Prize in Chemistry in 1958. Dr. Sanger invented a chemical method to sequence DNA for which he again received the Nobel Prize in Chemistry in 1980.
The sequencing of DNA became a hot field starting from late 1970s and it is still continuing without any sign of a slowdown. Many microbes, plants of agronomic value, and animals were targeted for genomics study. The first microbe whose genes (DNA) were sequences was that of a bacteria by the name Escherichia coli. Next, on the eukaryotic side the genome of baker's yeast was completely sequenced. Soon, the fruit fly's genome was sequenced. Now, the genomes of many species of mammals are being sequenced and the results are being compared for sequence homology and the orderliness of many genes is being studied.
The Australian marsupial kangaroo was targeted by the Australian biologists for the studies of genomics. The government in Australia established a center by the name 'Centre of Excellence for Kangaroo Genomics.' The Scientists from the center said they had for the first time mapped the genetic or nucleotide code of the Australian marsupials and found much of it was very similar to the genome for humans.
Biologists with genomics background had opined that there will be genetic similarities between kangaroo and human for sure but no one ever thought that clusters of genes will be same in these two groups of mammals. Perhaps during speciation the gene clusters were transferred from species to species. Dr. Jenny Graves, the center director of Australian kangaroo research put this finding this way; "We thought they'd be completely scrambled, but they're not. There is great chunks of the human genome which is sitting right there in the kangaroo genome."
In my view Dr. Graves should have said that the clusters of Kangaroo genes are sitting right in the human genome because humans have evolved from kangaroos. Evolutionary biologists think that humans' primitive ancestors have parted from kangaroos about 150 million years ago. Contrast this, if you may, with that of mice and humans. Human's ancestors have diverged from mice about 70 million years ago. The genomes of humans and mice show an astounding 95% plus sequence homology. Similarly, the chimps show a lot more sequence homology with humans than it is with mice. Conversely, the fruit fly and human genes show about 60% sequence homology. These results clearly show that Darwin 's theory of evolution is after all correct. Darwin was a naturalist who studied diversity of traits among animals. This he did at the time when no one knew what a gene is! In one hundred years or so the field of biology made so much progress that Darwin 's theory is now being applied to molecular biology. The fusion of evolutionary biology into molecular biology has spawned many new fields of study.
On a lighter side, it has not escaped my attention that humans still sport a pair of strong legs just as goats, cattle, kangaroos; consequently, humans could jump.The basketball players, soccer player etc., are adept in jumping; therefore, the genes controlling the muscle strength of legs in humans must have originated from kangaroo or the species that is the ancestor of Australian jumping marsupials.Try telling all these to a person who thinks that the biblical account of genesis is true.You surely will get a strange response.
Dr. A.H. Jaffor Ullah
- A researcher and columnist, writes from New Orleans, USA*