The modern working definition of a gene is a portion (or sequence) of DNA that codes for a known cellular function or process (e.g. the function make melanin molecules). A single 'gene' is most similar to a single 'word' in the English language.The nucleotides (molecules) that make up genes can be seen as 'letters' in the English language. Nucleotides are named according to which of the four nitrogenous bases they contain. The four bases are cytosine, guanine, adenine, and thymine.he modern working definition of a gene is a portion (or sequence) of DNA that codes for a known cellular function or process (e.g. the function make melanin molecules). A single 'gene' is most similar to a single 'word' in the English language.
Where did humans first appear on Earth, and what were their society, technology, and culture? Humans first appeared on Earth during the Paleolithic Era, in the steppes and savannah of Africa, before migrating to Eurasia, the Americas, and Australia. These humans were hunter-foragers, changing their tools and culture to adapt to their surroundings. Describe earliest humans' technology & tools.
View full size image. Modern humans may have dispersed in more than one wave of migration out of Africa, and they may have done so earlier than scientists had long thought, researchers now say. Modern humans first arose between 100,000 and 200,000 years ago in Africa.But when and how the modern human lineage then dispersed out of Africa has long been controversial. Scientists have suggested the exodus from Africa started between 40,000 and 70,000 years ago. multiple-dispersals scenario, with earlier modern humans leaving Africa as early as 130,000 before present, can perhaps account for part of the morphological and genetic patterns that we see among modern human populations..