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Biology/Have Human beings ALWAYS had 46 chromosomes?

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Expert: - 12/25/2008


Question
Have Human beings ALWAYS had 46 chromosomes? Even back in the 'cave-man' days (and before then)?
Considering how much we have evolved over time, would the number of chromosomes within us have differed?
Thanks in advance.

Answer
Dear Sonesh,

All members of the species Homo sapiens normally have 46 chromosomes.  Because we do not have samples of DNA from other subspecies of Homo sapiens (e.g., Homo sapiens neanderthalensis, the "Neanderthal Man"), we cannot say for sure what their chromosome complement was.

For the members of a single species to be able to breed together to produce fertile offspring, they must have the same number of chromosomes.  So yes, all Homo sapiens have always had 46 chromosomes as far as we know.

It's not really the number of chromosomes that determines a species identity, though.  It is the information on the DNA in those chromosomes that determines that.

Hope this helps.

Dana

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Dana Krempels, Ph.D.

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I can answer biology-related questions in the areas of evolution, zoology, botany, genetics, and ecology. But I don't answer homework questions or provide ideas for your science fair projects. So students please do your learning the right way by reading your text assignments and studying!

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At the University of Miami, I teach Evolution and Biodiversity, Botany, Zoology, Genetics, Ecology, and a variety of seminars (e.g., the Biology and Evolution of Human Gender Roles).

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I have a B.S. in Biology and an A.B. in English from the University of Southern California (1980). I earned my Ph.D. in Biology in the area of evolutionary biology/visual physiology from the University of Miami in 1989.

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I am currently an "expert" in both the "Rabbits" and "Wild Animals" categories.

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