填空题
All modern human originated in sub-Saharan Africa, according to a new study boasted by its founders as the "final blow" against an opposing viewpoint. Not so fast, says one anthropologist who finds flaws in the evidence.
The new study, published in the July 19 issue of the journal Nature, delivers what the researchers say could be the final verdict in support of the single point "Out of Africa" theory.
Manica and colleagues took multiple measurements of more than 4,500 male fossil skulls from 105 populations around the globe. They combined the results with data from studies of global genetic variations in humans, finding that both genetic and skull variability decreased with distance from Africa. So populations in southeastern Africa held the highest variability compared with populations in other countries.
The results held even when the scientists accounted for climate, since climate conditions can lead to changes in skull features. " In very cold climates you tend to generate a slightly thicker brow ridge. Whether or not that' s to keep horrible blizzards out of your eyes, I don' t know, " Amos said.
Past studies based on skull morphology have been weak and have supported both of the humanorigin views.
In his own research, Hawks is funding that natural selection has led to changes in thousands of genes during only the past few thousand years.
"I' m really thinking just the opposite of this paper, " Hawks said. "There are differences in the skull between populations, including their variability, but it is mostly due to very recent effects and not the origin of modern humans. "
The new study, published in the July 19 issue of the journal Nature, delivers what the researchers say could be the final verdict in support of the single point "Out of Africa" theory.
Manica and colleagues took multiple measurements of more than 4,500 male fossil skulls from 105 populations around the globe. They combined the results with data from studies of global genetic variations in humans, finding that both genetic and skull variability decreased with distance from Africa. So populations in southeastern Africa held the highest variability compared with populations in other countries.
The results held even when the scientists accounted for climate, since climate conditions can lead to changes in skull features. " In very cold climates you tend to generate a slightly thicker brow ridge. Whether or not that' s to keep horrible blizzards out of your eyes, I don' t know, " Amos said.
Past studies based on skull morphology have been weak and have supported both of the humanorigin views.
In his own research, Hawks is funding that natural selection has led to changes in thousands of genes during only the past few thousand years.
"I' m really thinking just the opposite of this paper, " Hawks said. "There are differences in the skull between populations, including their variability, but it is mostly due to very recent effects and not the origin of modern humans. "