How ancient DNA may help in understanding the origin and spread of agriculture

The origin and spread of agriculture have been central questions in archaeo logy for the last are increasingly being addressed by a multidisciplinary a pproach involving biologists, ecologists, geographers and anthropologists a s well as archaeologists. Molecular genetics has the potential to make an i mportant contribution, especially by enabling the number of times that a cr op or animal was domesticated to be determined. Molecular genetics can also assign approximate dates to domestication events, identify the wild progen itor of a domesticate, and provide new forms of evidence relevant to agricu ltural spread. With wheat, molecular genetical studies of modern plants hav e suggested that einkorn was domesticated just once but that emmer might ha ve been domesticated more than once. Ancient DNA studies of animal remains have benefited from progress made with equivalent analyses of human bones, and with plant material there have been clear demonstrations of DNA preserv ation in desiccated seeds. Charred remains have also been shown to contain ancient DNA but this finding is unexpected in view of the high temperatures to which these seeds have supposedly been exposed. Ancient DNA studies of wheat remains have been used in taxonomic identification and in assessment of the possible breadmaking quality of the wheat grown at an Early Bronze A ge site in Greece.