It is distressing to observe that today some nations are at perpetual war, many provinces within many countries are at loggers head and several communities have not been able to overcome their traditional, irrational hatred for others even within their own religious and family domains. It may not be widely known that among all humans 99.9% base pairs of genes are common (out of the nearly three billion base pairs of genes). Differences visible to us result from only 0.1% of complex genetic variations and the novel genes that arise and get added to our genomes due to mutations in DNA.
Humans have large genetic similarity with most of the animals; about 60% with chicken and cows, about 80% with dogs and horses and about 90% with cats. Chimpanzees are genetically 96% to 98% similar to humans. (Carl Zimmer in National Geographic, July 2013). Even plant life has genes common with animals as well as human beings. Though all species are unique, their genetic codes are not identical. However, common heritage of almost all forms of living beings, humans in particular, is certainly beyond any doubt. It is interesting to note that since more than two centuries, scientists have been trying to discover the common ancestor of all forms of life on earth. This study has led to efforts to identify what is known as the Last Universal Common Ancestor (LUCA).
French scientist Pierre Louis was the first to suggest that all forms of life had a common ancestor, followed by Immanuel Kant, Charles Darwin (1794) and many more till today. In July 2016, Wade Nicholas reported (New York Times) that 355 common genes had been identified by comparing genomes of the three main domains of living systems that have existed since more than 3.9 billion years; namely, bacteria, archaea and eukaryotes). More than 10,000 species of bacteria are known so far. The very large number of single-celled micro-organisms (that have no nuclei), called archaea, can survive in very severe environmental conditions. Multi-cellular creatures that enclose nuclei within their cell membranes, known as eukaryotes, include fungi, algae, plants, animals and humans. The number of cells in these could be as high as 30,000 billion which makes these investigations extremely difficult. In near future, the identification of more common genes in these three domains may lead to discovery of the Universal Common Ancestor.