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THE FAMILY AND THE NATION
Life originated on planet Earth 600 million years ago. The continental drift occurred 200 million years ago, creating five continents. Mammals evolved 140 million years ago. The earliest human type, called Hominid, evolved 26 million years ago. Modern man evolved out of Hominid some 200,000 years ago. He migrated across the planet as hunter-gatherer before settling down in communities only in the last 50,000 years. The spoken language is some 10,000 years old while writing evolved only in the last few thousand years. Civilization, as we see it today, has emerged within the short span of 200 to 400 generations, that is, 5,000 to 10,000 years ago. Is there a genetic continuity?
Newer genetic technologies have given us better insight into retracing the history of man. In the words of Michael Hammer, Professor of Genomic Analysis at the University of Arizona, 'The DNA of a human being is his history book. Millions of people around the world can trace their ancestry back several generations or more through oral history, family documents or government records of such events as marriages and births. The history contained in human genes also links every person on Earth to a common genetic origin in Africa. Natural variations in the genes occurred over time as people migrated out of Africa. The DNA (deoxyribonucleic acid) evolved, mutated and changed. It is probably during the 30,000-50,000 years of co-existence that societies evolved, adopting newer innovations and cultures. By the nature of human migration and mixing in the past, we have not remained separate and isolated on different continents all these years. We do have a history of migration and our genome reflects that.
So there is genetic continuity. While a gene resides in a particular chromosome, it does not necessarily remain there in the next generation. The physical material of heredity is not, as had been generally supposed, protein, but DNA. The
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