Mummy DNA intact after 2,400 years.In a remarkable application of recombinant DNA recombinant DNA n. Genetically engineered DNA prepared by transplanting or splicing one or more segments of DNA into the chromosomes of an organism from a different species. Such DNA becomes part of the host's genetic makeup and is replicated. techniques, a Swedish scientist has reproduced in bacteria segments of DNA DNA: see nucleic acid. DNA or deoxyribonucleic acid One of two types of nucleic acid (the other is RNA); a complex organic compound found in all living cells and many viruses. It is the chemical substance of genes. isolated from an Egyptian mummy. An analysis of one of these segments -- 3,400 base pairs long -- shows it suffered little damage over the two millennia of preservation. This work and the recent cloning of DNA fron a quagga quagga (kwăg`ə), extinct type of zebra. It formerly inhabited open plains in S Africa, where its range overlapped that of the common zebra (Equus burchelli). , an extinct horselike animal (SN: 6/9/84, p. 356), "raise the hope that recombinant DNA techniques may be applied systematically to archaeological samples," says Svante Paabo of the University of Uppsala. No genes have been identified in the DNA fragment, but it contains regions, known as Alu repeated sequences, which are characteristic of human DNA, Paabo reports in the April 18 NATURE. "The DNA fragments seem to contain little or no modifications introduced postmortem postmortem /post·mor·tem/ (post-mort´im) performed or occurring after death. post·mor·tem adj. Relating to or occurring during the period after death. n. See autopsy. ," he notes. DNA was detectable in three of 23 mummies examined, but only in one case, the mummy of an infant, did Paabo succeed in inserting the DNA pieces into carrier rings (plasmids) and reproducing them in bacteria. The DNA was taken from the skin and some underlying tissue of the mummy infant's left leg. The yield of DNA from the mummy infant proved to be high--about 5 percent of the yield generally obtained from fresh human tissue. "These results," Paabo says, "establish the feasibility of faithfully cloning substantial pieces of genomic [chromosomal] DNA from bilogical remains of great antiquity." Paabo suggests that researchers should now begin to study both the evolution of ancient populations in the Nike Valley. The examination need not be limited to Egyptian history -- preserved human remains have been found on several continents, including South America and Europe. But there is a fascination with ancient Egypt. DNA analysis DNA analysis Any technique used to analyze genes and DNA. See Chromosome walking, DNA fingerprinting, Footprinting, In situ hybridization, Jeffries' probe, Jumping libraries, PCR, RFLP analysis, Southern blot hybridization. might elaborate on relationships between pharaonic dynasties, Paabo says, as well as between members of pharaonic families. Geneticist ge·net·i·cist n. A specialist in genetics. geneticist a specialist in genetics. geneticist J.S. Jones of University College in London adds, in the same issue of NATURE, that ancient records suggest the Egyptian royal family practiced incest in order to preserve the bloodline blood·line n. The direct line of descent; a pedigree. of a deity. "There is something intriguing," says Jones, "about the possibility of learning the genotype of a god. "The interaction of DNA technology and archaeology may open a new phase in our understanding of human history," Jones says. But he stresses that it is a research approach, not a mummy, that is coming to life: "We cannot of course reconstitute re·con·sti·tute tr.v. re·con·sti·tut·ed, re·con·sti·tut·ing, re·con·sti·tutes 1. To provide with a new structure: The parks commission has been reconstituted. 2. a functional gene (let alone a living individual) from this short repeated sequence." |
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