Neandertal mans Are Not Our Ancestors Essay, Research Paper
7-11-97
University Park, Pa. & # 8212 ; A squad of U.S. and German research workers has extracted mitochondrial Deoxyribonucleic acid from Neandertal bone demoing that the Neandertal DNA sequence falls outside the normal fluctuation of modern worlds.
& # 8220 ; These consequences indicate that Neandertal mans did non lend mitochondrial DNA to modern worlds, & # 8221 ; says Dr. Mark Stoneking, associate professor of anthropology at Penn State. & # 8220 ; Neandertal mans are non our ancestors. & # 8221 ;
The research besides reaffirms the beginnings of modern worlds in Africa. Reporting in today & # 8217 ; s ( July 11 ) issue of the diary Cell, the research workers detail their methods and the consequences of analysis of Neandertal mitochondrial DNA. The research squad includes Matthias Krings, alumnus pupil, and Dr. Svante Paabo, professor of fauna, University of Munich ; Dr. Ann Stone, postdoctoral chap, University of Arizona ; Ralf W. Schmitz and Heike Krainitzki of Rhineland Museum, Bonn, Germany ; and Stoneking.
Current theory holds that Neandertals became nonextant merely 30,000 old ages ago and co-existed with modern worlds in Europe. The squad, nevertheless, found that Neandertals and modern worlds diverged genetically 500,000 to 600,000 old ages ago, proposing that though they may hold lived at the same clip, Neandertal mans did non lend familial stuff to modern worlds.
Since 1991, an interdisciplinary undertaking of the Rhineland Museum, headed by Schmitz, has focused on the Neandertal-type specimen. This specimen was found in 1856 near Dusseldorf, Germany. As a portion of this undertaking, a sample was removed for DNA analysis.
& # 8220 ; The ability to pull out DNA from ancient bone is dependent on many factors, including saving, temperature and humidness, & # 8221 ; says Stoneking, a module member in Penn State & # 8217 ; s College of the Liberal Arts.
Paabo antecedently showed that even if pull outing ancient DNA is possible, it tends to be damaged and degraded, giving merely short fragments. The research workers used a method of overlapping short strands of DNA to obtain a mitochondrial DNA sequence of 378 base brace. To guarantee that mistakes caused by damaged DNA were non incorporated into the sequence and that modern human Deoxyribonucleic acid did non pollute the samples, the research workers ran multiple extractions and elaborations. They besides sent a sample to Penn State & # 8217 ; s Anthropological Genetics Laboratory where Stone, so a Ph.D. campaigner at Penn State, ran a parallel extraction and elaboration of the Deoxyribonucleic acid.
To get down elaboration, the research workers used two human primers & # 8212 ; little pieces of Deoxyribonucleic acid that match the beginning of the sequence to be amplified.
& # 8220 ; The first two human primers we chose worked, & # 8221 ; says Stoneking. & # 8220 ; It turns out this was a lucky choice. & # 8221 ;
To look into that the amplified DNA was truly Neanderthal, the research workers prepared primers based on their extracted sample and ran them on legion human Deoxyribonucleic acid samples.
& # 8220 ; The Neandertal primers did non magnify any human DNA, & # 8221 ; says Stoneking. & # 8220 ; Most human primers would likely non work on Neandertal DNA. & # 8221 ;
The research workers compared the Neandertal sequence with 2,051 human sequences and 59 common Pan troglodytes sequences. They found that the differences in Neandertal DNA occurred at sites where differences normally occur in both worlds and Pan troglodytess.
& # 8220 ; The alterations reflect the evolutionary form typical of mitochondrial DNA sequences of life worlds and Pan troglodytess, non that of random harm or debasement, & # 8221 ; says Stoneking.
When the research workers looked at the Neandertal sequence with regard to 994 human mitochondrial Deoxyribonucleic acid line of descents including Africans, Europeans, Asians, Native Americans, Australians and Pacific Islanders, they found the figure of base brace differences between the Neandertal sequence and these groups was 27 or 28 for all groups.
& # 8220 ; While Neandertal mans inhabited the same geographic part as modern-day Europeans, the ascertained differences between the Neandertal sequence and modern Europeans do non bespeak a closer relationship to modern Europeans than to other modern-day human populations, & # 8221 ; says Stoneking. The research workers used phyletic tree Reconstruction & # 8212 ; a method that uses mitochondrial DNA to put single groups in comparative relationship & # 8212 ; to look into the consequences of their pair-wise DNA comparings. The trees show that the Neandertal sequence subdivisions before the divergency of the assorted human mitochondrial Deoxyribonucleic acid line of descents, but after the split from Pan troglodytess.
This phyletic tree besides shows that the first three subdivisions of worlds are of African beginning, with merely the 4th subdivision demoing non-African sequences.
& # 8220 ; The ramification form indicates that the ascendant of the mitochondrial DNA cistron pool of modern-day worlds lived in Africa, & # 8221 ; says Stoneking of Penn State.
The research workers are confident with their consequences, but they caution that they are derived from merely one person. They besides warn that Deoxyribonucleic acid may be hard to pull out from other specimens. While the consequences indicate that Neandertal mans did non lend mitochondrial DNA to modern worlds, it is still possible that they contributed other cistrons.
**aem**
Editors: For more information or interviews, reach A & # 8217 ; ndrea Elyse Messer, scientific discipline and research information officer, at ( 814 ) 865-9481 ( office ) ; 867-1774 ( place ) or at aem1 @ psu.edu by electronic mail.
Contact:
A & # 8217 ; ndrea Elyse Messer ( 814 ) 865-9481 ( O ) ( 814 ) 867-1774 ( H ) aem1 @ psu.edu
Vicki Fong 814-865-9481 ( o ) 814-238-1221 ( H
) vyf1 @ psu.edu
Bibliography
7-11-97
University Park, Pa. & # 8212 ; A squad of U.S. and German research workers has extracted mitochondrial Deoxyribonucleic acid from Neandertal bone demoing that the Neandertal DNA sequence falls outside the normal fluctuation of modern worlds.
& # 8220 ; These consequences indicate that Neandertal mans did non lend mitochondrial DNA to modern worlds, & # 8221 ; says Dr. Mark Stoneking, associate professor of anthropology at Penn State. & # 8220 ; Neandertal mans are non our ancestors. & # 8221 ;
The research besides reaffirms the beginnings of modern worlds in Africa. Reporting in today & # 8217 ; s ( July 11 ) issue of the diary Cell, the research workers detail their methods and the consequences of analysis of Neandertal mitochondrial DNA. The research squad includes Matthias Krings, alumnus pupil, and Dr. Svante Paabo, professor of fauna, University of Munich ; Dr. Ann Stone, postdoctoral chap, University of Arizona ; Ralf W. Schmitz and Heike Krainitzki of Rhineland Museum, Bonn, Germany ; and Stoneking.
Current theory holds that Neandertals became nonextant merely 30,000 old ages ago and co-existed with modern worlds in Europe. The squad, nevertheless, found that Neandertals and modern worlds diverged genetically 500,000 to 600,000 old ages ago, proposing that though they may hold lived at the same clip, Neandertal mans did non lend familial stuff to modern worlds.
Since 1991, an interdisciplinary undertaking of the Rhineland Museum, headed by Schmitz, has focused on the Neandertal-type specimen. This specimen was found in 1856 near Dusseldorf, Germany. As a portion of this undertaking, a sample was removed for DNA analysis.
& # 8220 ; The ability to pull out DNA from ancient bone is dependent on many factors, including saving, temperature and humidness, & # 8221 ; says Stoneking, a module member in Penn State & # 8217 ; s College of the Liberal Arts.
Paabo antecedently showed that even if pull outing ancient DNA is possible, it tends to be damaged and degraded, giving merely short fragments. The research workers used a method of overlapping short strands of DNA to obtain a mitochondrial DNA sequence of 378 base brace. To guarantee that mistakes caused by damaged DNA were non incorporated into the sequence and that modern human Deoxyribonucleic acid did non pollute the samples, the research workers ran multiple extractions and elaborations. They besides sent a sample to Penn State & # 8217 ; s Anthropological Genetics Laboratory where Stone, so a Ph.D. campaigner at Penn State, ran a parallel extraction and elaboration of the Deoxyribonucleic acid.
To get down elaboration, the research workers used two human primers & # 8212 ; little pieces of Deoxyribonucleic acid that match the beginning of the sequence to be amplified.
& # 8220 ; The first two human primers we chose worked, & # 8221 ; says Stoneking. & # 8220 ; It turns out this was a lucky choice. & # 8221 ;
To look into that the amplified DNA was truly Neanderthal, the research workers prepared primers based on their extracted sample and ran them on legion human Deoxyribonucleic acid samples.
& # 8220 ; The Neandertal primers did non magnify any human DNA, & # 8221 ; says Stoneking. & # 8220 ; Most human primers would likely non work on Neandertal DNA. & # 8221 ;
The research workers compared the Neandertal sequence with 2,051 human sequences and 59 common Pan troglodytes sequences. They found that the differences in Neandertal DNA occurred at sites where differences normally occur in both worlds and Pan troglodytess.
& # 8220 ; The alterations reflect the evolutionary form typical of mitochondrial DNA sequences of life worlds and Pan troglodytess, non that of random harm or debasement, & # 8221 ; says Stoneking.
When the research workers looked at the Neandertal sequence with regard to 994 human mitochondrial Deoxyribonucleic acid line of descents including Africans, Europeans, Asians, Native Americans, Australians and Pacific Islanders, they found the figure of base brace differences between the Neandertal sequence and these groups was 27 or 28 for all groups.
& # 8220 ; While Neandertal mans inhabited the same geographic part as modern-day Europeans, the ascertained differences between the Neandertal sequence and modern Europeans do non bespeak a closer relationship to modern Europeans than to other modern-day human populations, & # 8221 ; says Stoneking. The research workers used phyletic tree Reconstruction & # 8212 ; a method that uses mitochondrial DNA to put single groups in comparative relationship & # 8212 ; to look into the consequences of their pair-wise DNA comparings. The trees show that the Neandertal sequence subdivisions before the divergency of the assorted human mitochondrial Deoxyribonucleic acid line of descents, but after the split from Pan troglodytess.
This phyletic tree besides shows that the first three subdivisions of worlds are of African beginning, with merely the 4th subdivision demoing non-African sequences.
& # 8220 ; The ramification form indicates that the ascendant of the mitochondrial DNA cistron pool of modern-day worlds lived in Africa, & # 8221 ; says Stoneking of Penn State.
The research workers are confident with their consequences, but they caution that they are derived from merely one person. They besides warn that Deoxyribonucleic acid may be hard to pull out from other specimens. While the consequences indicate that Neandertal mans did non lend mitochondrial DNA to modern worlds, it is still possible that they contributed other cistrons.
**aem**
Editors: For more information or interviews, reach A & # 8217 ; ndrea Elyse Messer, scientific discipline and research information officer, at ( 814 ) 865-9481 ( office ) ; 867-1774 ( place ) or at aem1 @ psu.edu by electronic mail.
Contact:
A & # 8217 ; ndrea Elyse Messer ( 814 ) 865-9481 ( O ) ( 814 ) 867-1774 ( H ) aem1 @ psu.edu
Vicki Fong 814-865-9481 ( o ) 814-238-1221 ( H ) vyf1 @ psu.edu
