ram%shukra@Sun.COM (Renu Raman, Sun Microsystems) (08/24/87)
To-day, when a friend of mine related to me a story of how a friend
of his has no recollection of his birth date, it struck upon me on
the availibilty/non-availability of a clinical/bilogically accurate
technique of determining human age (while a person is still alive).
Are there any techniques (like carbon dating) to determine a living
human's age (Accurate to within a month/week at least)? My
knowledge of biology and/or human anoanotmy&physilogy is not
more than high-school level. So, anybody know of any techniques
that can succesfully determine the age of a person? A simple
technique (invasive/non-invasive) could be useful in determining the
ages of many natives/tribes of the African & South American and many
thirld world nations were records of birth (as well as death) are
not kept.
---------------------
Renu Raman ARPA:ram@sun.com
Sun Microsystems UUCP:{ucbvax,seismo,hplabs}!sun!ram
M/S 5-40, 2500 Garcia Avenue,
Mt. View, CA 94043oliver@unc.cs.unc.edu (Bill Oliver) (08/24/87)
In article <26333@sun.uucp> ram%shukra@Sun.COM (Renu Raman, Sun Microsystems) writes: > > Are there any techniques (like carbon dating) to determine a living > human's age (Accurate to within a month/week at least)? My In children, if one assumes adequate nutrition, it is possible to get fairly close by looking at bone growth and maturation. In adults, it is only possible to roughly group a person into a general age category (young adult, middle age, old middle age, etc.). Bill Oliver
larry@kitty.UUCP (Larry Lippman) (08/25/87)
In article <26333@sun.uucp>, ram%shukra@Sun.COM (Renu Raman, Sun Microsystems) writes: > Are there any techniques (like carbon dating) to determine a living > human's age (Accurate to within a month/week at least)? My > knowledge of biology and/or human anoanotmy&physilogy is not > more than high-school level. So, anybody know of any techniques > that can succesfully determine the age of a person? There are a number of techniques which may be used to ascertain the approximate age of a human being; unfortunately, most of them can only be applied to _dead_ human beings. :-) First of all, radiocarbon dating (C14) only works on living matter that is now dead. C14 intake stops at death, and the decay of residual C14 is used to determine absolute age. Radiocarbon dating can be used to ascertain age up to about 50,000 years. While radiocarbon dating is accurate to +/- 40 years, specimens which are less than 200 years old cannot be dated by this method. Other techniques for dating bone include: fluorine dating (a purely chemical measurement); uranium dating (isotope decay); nitrogen dating (chemical measurement of collagen in bone); and racemization of amino acids in bones (chemical measurement of amino acid isomer mixtures). Unfortunately, the above techniques only work on dead specimens and determine their absolute age (but not relative age at death). The only satisfactory method of age determination in living and dead contemporary specimens is through examination of skeletal structures. Some techniques which I will describe are only applicable to direct examination of skeletal remains; other techniques may be used through x-ray examination, and therefore could be applied to living humans. In general, the precision to which human age can be determined decreases as the subject becomes older. The most common method of age determination is through the appearance of unique bone structures which are called "ossification centers". Examination of ossification centers can determine age with a precision of +/- 1 month from birth to about 2 years; from 2 to 3 years the precision is +/- 2 months; from 3 to 5 years the precision is +/- 6 months. Vertebral ossification can be used to establish age from about 6 to 12 years with a precision of about +/- 1 year. The emergence of teeth is useful to determine age from about 6 to 14 years, with a precision of about +/- 1 year. The study of epiphysial union can be used to determine age from about 12 years to about 30 years. An "epiphysis" is a piece of bone which is joined to a larger bone via a cartilagenous bridge; after a certain age, union occurs as the cartilage is replaced by bone, and the epiphysis becomes part of the main bone. Examination of closure of cranial "sutures" has been used, but is not considered that reliable. Examination of changes in the scapula (shoulder blade) through transillumination or x-rays can be used to determine age in older persons up to the 80's or more. Other areas of bone "wear" such as the glenoid fossa (part of the skull into which the lower jaw fits), clavicular facet (part of the collarbone), acromial process (the "point" of the shoulder), etc. can be used to determine age in older subjects. The best age determination precision in subjects older than 40 years is +/- 10 years. Generally, as many skeletal points as possible are examined, and a statistical "score" is taken to arrive at a mean age figure. So, to sum up: there is no method of age determination in either living or dead subjects beyond that which I have described above. <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|seismo|utzoo}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"
peter@sugar.UUCP (08/29/87)
How about isotope proportions in tooth enamel? That should be usable if (as I have been given to believe) the enamel is not replaced after eruption of the secondary teeth. -- -- Peter da Silva `-_-' ...!seismo!soma!uhnix1!sugar!peter -- U <--- not a copyrighted cartoon :->
palmer@tybalt.caltech.edu.UUCP (08/31/87)
In article <1960@kitty.UUCP> larry@kitty.UUCP (Larry Lippman) writes: > First of all, radiocarbon dating (C14) only works on living matter >that is now dead. C14 intake stops at death, and the decay of residual >C14 is used to determine absolute age. Radiocarbon dating can be used >to ascertain age up to about 50,000 years. While radiocarbon dating is >accurate to +/- 40 years, specimens which are less than 200 years old >cannot be dated by this method. If the technical problems with C14 dating of objects <200 years old could be solved (assuming that they are merely technical problems) could we date people by the C14 in their DNA in their nervous system? Since neurons do not reproduce (much) after birth, the DNA does not change (does it?) so the same carbon atoms remain in the DNA as at birth. I do not volunteer for this experiment. David Palmer palmer@tybalt.caltech.edu ...rutgers!cit-vax!tybalt.caltech.edu!palmer The opinions expressed are those of an 8000 year old Atlantuan priestess named Mrla, and not necessarily those of her channel.
dd@beta.UUCP (08/31/87)
In article <3836@cit-vax.Caltech.Edu>, palmer@tybalt.caltech.edu (David Palmer) writes: > Since neurons do not reproduce (much) after birth, the DNA does not > change (does it?) so the same carbon atoms remain in the DNA as at birth. Nope. DNA is repaired even if the neuron does not divide. Thus the turn- over time, while long (I don't know the exact number, but I'd bet it's well under a year) is finite. If I remember correctly, the only compounds which are not turned over are the collagen-containing tendons and ligaments. I suspect the latest version of Principles of Biochemistry (White et al.) will have the details. dan davison/theoretical biology/t-10 ms k710/Los Alamos National Lab/Los Alamos, NM 87545. "I'm a doctor, not an elevator" Dr. McCoy
thomas%spline.uucp@utah-gr.UUCP (Spencer W. Thomas) (09/02/87)
There was an item on "Weekend Edition" last Sunday about a "Baltimore
study on aging". They have been following a number of people for many
years, looking at what happens to them as they get older. One of the
doctors said that if he had all the information about a person that
the "study" has (excluding their actual age, I assume), he would not
be able to do as well at guessing their age as the guy at the
carnival.
So, it's a hard problem...
=Spencer ({ihnp4,decvax}!utah-cs!thomas, thomas@cs.utah.edu)palmer@tybalt.caltech.edu.UUCP (09/03/87)
Does anybody know what genetic material makes up a fruit (such as an apple). Is it the same as the "mother" (host) tree, or is it the same as in the seeds. Are all the seeds in the fruit clones (identical twins)? David Palmer palmer@tybalt.caltech.edu ...rutgers!cit-vax!tybalt.caltech.edu!palmer The opinions expressed are those of an 8000 year old Atlantuan priestess named Mrla, and not necessarily those of her channel.
cipher@mmm.UUCP (Andre Guirard) (09/03/87)
In article <2131@utah-gr.UUCP> thomas%spline.UUCP@utah-gr.UUCP (Spencer W. Thomas) writes: >doctor said that if he had all the information about a person that >the "study" has (excluding their actual age, I assume), he would not >be able to do as well at guessing their age as the guy at the >carnival. Sounds like they should hire one of these carnival guys to tell them what to look for. For the ones I've seen, the mark ``wins'' if the carnie doesn't get within five years of the right age. The mark ``wins'' often. But the prizes aren't worth very much, so it doesn't much matter. The doctor may be overestimating the ability of the guy at the carnival. -- | Andre Guirard "Open the door before you come in, Spike." | inhp4!mmm!cipher "Oh. Sorry, boss." | "Wake me up for | the good part."
werner@aecom.YU.EDU (Craig Werner) (09/04/87)
In article <3867@cit-vax.Caltech.Edu>, palmer@tybalt.caltech.edu (David Palmer) writes: > Does anybody know what genetic material makes up a fruit (such as an apple). > Is it the same as the "mother" (host) tree, or is it the same as in > the seeds. Are all the seeds in the fruit clones (identical twins)? > > David Palmer As a matter of botany, an apple is technically not a fruit. The apple is an accessory, the fruit is the core. The seeds are fraternal twins, not identical, as each arises from a pollen grain (the plant equivalent of spermatazoa) fertilizing an ovum. Hence, the cells of an apple contain the cells of the tree. The cells of the fruit (i.e., the core) do similarly. The seeds are generally different due to meiotic recombination, although they can be damn similar if the tree is self-fertilizing. While I'm recounting my botany, let me relay the following useless information: The blueberry is not biologically a berry. Like an apple, it is an accessory, with a fruit core. The strawberry is not biologically a berry. Each "seed" in a strawberry is a complete fruit. It is therefore referred to as an aggregate. A blackberry is no biologically a berry. Ditto. An orange. That's biologically a berry. -- Craig Werner (future MD/PhD, 3 years down, 4 to go) werner@aecom.YU.EDU -- Albert Einstein College of Medicine (1935-14E Eastchester Rd., Bronx NY 10461, 212-931-2517) "Beware of Yuppies bearing Uzis."
emigh@ncsugn.ncsu.edu (Ted H. Emigh) (09/04/87)
In article <3867@cit-vax.Caltech.Edu> palmer@tybalt.caltech.edu.UUCP (David Palmer) writes: >Does anybody know what genetic material makes up a fruit (such as an apple). >Is it the same as the "mother" (host) tree, or is it the same as in >the seeds. Are all the seeds in the fruit clones (identical twins)? Mother. No (Half Sibs). -- Ted H. Emigh, Dept. Genetics and Statistics, NCSU, Raleigh, NC uucp: mcnc!ncsuvx!ncsugn!emigh internet: emigh%ncsugn.ncsu.edu BITNET: NEMIGH@TUCC @ncsuvx.ncsu.edu:emigh@ncsugn.ncsu.edu
jnp@calmasd.GE.COM (John Pantone) (09/04/87)
(Andre Guirard) writes: > (Spencer W. Thomas) writes: > >doctor .... would not be able to do as well at guessing ... age as > >the guy at the carnival. > > Sounds like they should hire one of these carnival guys to tell them > what to look for. If they did - they would be very dissapointed. A good friend of my family was a carny for many years. Among other specialties he did an age-guessing concession. According to him the giveaways are clothing styles and speech patterns. Given a generalized guess based on the person's physical appearance he would further refine the guess with info based on the style and age of their shoes, accessories (purses, watches, etc.) and then try to get them to talk to their companions - to detect any key slang phrases which would help pin down the age. He hastened to add that this worked only (for him anyway) with what he called the "typical white rural types" and that he couldn't handle any other racial/ethnic groups anywhere near as well. So, the conclusion is that the carnies are using social clues as their principal information, not the "body" of the person - at least not exclusively. -- These opinions are solely mine and in no way reflect those of my employer. John M. Pantone @ GE/Calma R&D, Data Management Group, San Diego ...{ucbvax|decvax}!sdcsvax!calmasd!jnp jnp@calmasd.GE.COM
peter@sugar.UUCP (09/11/87)
Couln't you do some sort of radioisotope testing on tooth enamel, and at least get the age since dentition? -- -- Peter da Silva `-_-' ...!seismo!soma!uhnix1!sugar!peter -- 'U` <-- Public domain wolf.
larry@kitty.UUCP (Larry Lippman) (09/12/87)
In article <694@sugar.UUCP>, peter@sugar.UUCP (Peter da Silva) writes: > Couln't you do some sort of radioisotope testing on tooth enamel, and at least > get the age since dentition? There are two problems that I see with this idea: 1. Carbon-14 has a half-life of approximately 5,730 years. Since the age of a living person is one percent or less of this value, one would be extremely hard pressed to obtain the required resolution using a scintillation counter. Also, there is uncertainty in the C14 half-life, and it is typically expressed as 5,730 +/- 40 years. There is just no practicable way to measure such a slight amount of C14 decay. 2. While I don't claim to have an in-depth understanding of tooth physiology, it would seem to me that there would be some migration of comtemporary C14 into the enamel, thereby nullifying any attempt to perform age calculations even IF the C14 decay could be measured. <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|seismo|utzoo}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"
eddy@boulder.UUCP (09/13/87)
In article <2001@kitty.UUCP> larry@kitty.UUCP (Larry Lippman) writes: >In article <694@sugar.UUCP>, peter@sugar.UUCP (Peter da Silva) writes: >> Couln't you do radioisotope testing on tooth enamel, and at least >> get the age since dentition? > > There are two problems that I see with this idea: > >1. Carbon-14 has a half-life of approximately 5,730 years. Since the >2. While I don't claim to have an in-depth understanding of tooth > physiology, it would seem to me that there would be some migration > of comtemporary C14 into the enamel, thereby nullifying any attempt > to perform age calculations even IF the C14 decay could be measured. I am poorly informed on this, but a textbook of mine (it's a freshman text for a class I'm TA for) mentions briefly that you can date the age of a human by tooth enamel. No new protein is laid down in the tooth, so there is no amino acid turnover during one's lifetime. Amino acids are normally left-handed, but will slowly racemize and head for equilibration between right- and left- handed forms, if left alone like in tooth enamel (or in the crystallins on the lens of the eye). The book claims that a measure of right- vs. left-handedness in the amino acids of the tooth can provide a fair measure of one's age. No radioisotopes necessary. Voila! - Sean Eddy - MCD Biology; U. of Colorado at Boulder; Boulder CO 80309 - eddy@boulder.colorado.EDU !{hao,nbires}!boulder!eddy
larry@kitty.UUCP (Larry Lippman) (09/13/87)
In article <2195@sigi.Colorado.EDU>, eddy@boulder.Colorado.EDU (Sean Eddy) writes: > I am poorly informed on this, but a textbook of mine (it's a > freshman text for a class I'm TA for) mentions briefly that you > can date the age of a human by tooth enamel. No new protein is > laid down in the tooth, so there is no amino acid turnover during > one's lifetime. Amino acids are normally left-handed, but will > slowly racemize and head for equilibration between right- and > left- handed forms, if left alone like in tooth enamel (or > in the crystallins on the lens of the eye). The book > claims that a measure of right- vs. left-handedness in the amino > acids of the tooth can provide a fair measure of one's age. I am slightly familiar with the chemistry behind dating bones through racemization. However, I have only seen this applied to archeological specimens with ages from hundreds of years to 100,000+ years. In this application, isoleucine is one amino acid that is used; it has a racemization "half-life" of something like 100,000 years at ambient temperature. The racemization is L-isoleucine <--> D-alloisoleucine. L-aspartic acid is also used; it has a "half-life" of something like 15,000 years at ambient temperatures. The racemization here is L-aspartic acid <--> D-aspartic acid. In view of the long racemization "half-life" times of the above amino acids, I have doubts that any other suitable amino acid would racemize in a short enough time to provide a useful resolution in living subjects. <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|seismo|utzoo}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"
eddy@boulder.Colorado.EDU (Sean Eddy) (09/13/87)
In article <2003@kitty.UUCP> larry@kitty.UUCP (Larry Lippman) writes: > I am slightly familiar with the chemistry behind dating bones >through racemization. However, I have only seen this applied to >archeological specimens with ages from hundreds of years to 100,000+ years. > In this application, isoleucine is one amino acid that is used; >it has a racemization "half-life" of something like 100,000 years at >ambient temperature. The racemization is L-isoleucine <--> D-alloisoleucine. > L-aspartic acid is also used; it has a "half-life" of something >like 15,000 years at ambient temperatures. The racemization here is >L-aspartic acid <--> D-aspartic acid. > In view of the long racemization "half-life" times of the above >amino acids, I have doubts that any other suitable amino acid would >racemize in a short enough time to provide a useful resolution in living >subjects. Ah, yes. I told you I didn't know what I was talking about. Thanks for the clarification... ...but I'm not satisfied yet. My wonderful little biology text (which I hate, so I don't care if it's wrong) tries to convince me that dating by racemization is being used to check the validity of claims to incredible old age, such as those made by these people in Peru or the Caucasus. Perhaps some amino acids have reasonably short racemization half-times? Or alternatively, detection of D-amino acids is very precise (since there are absolutely none whatsoever in the protein to start with, any D-amino acid constitutes signal and not background)? - Sean Eddy - MCD Biology; U. of Colorado at Boulder; Boulder CO 80309 - eddy@boulder.colorado.EDU !{hao,nbires}!boulder!eddy
bob@bio73.unsw.oz (Robert Stanley Vickery) (09/13/87)
re: david palmer's question on the genetic make-up of apples. the apple 'fruit' is derived from the mother tree. the seeds contain genes from the female parent and from the pollen parent. they are all different. apple varieties are propagated vegetatively in a very complicated procedure.
peter@sugar.UUCP (09/16/87)
In article <2001@kitty.UUCP>, larry@kitty.UUCP (Larry Lippman) writes: > In article <694@sugar.UUCP>, peter@sugar.UUCP (Peter da Silva) writes: > > Couln't you do some sort of radioisotope testing on tooth enamel, > > and at least get the age since dentition? > 1. Carbon-14 has a half-life of approximately 5,730 years... > 2. ... some migration of comtemporary C14 into the enamel,... Carbon-14 isn't the only radioisotope used in this sort of thing, is it? What about shorter-lived isotopes that (while not longevious enough for archeology) would decay fast enough to be useful here? -- -- Peter da Silva `-_-' ...!hoptoad!academ!uhnix1!sugar!peter -- 'U` ^^^^^^^^^^^^^^ Not seismo!soma (blush)
mwj@a.UUCP (William Johnson) (09/19/87)
In article <763@sugar.UUCP>, peter@sugar.UUCP (Peter da Silva) writes: > Carbon-14 isn't the only radioisotope used in this sort of thing, is it? What > about shorter-lived isotopes that (while not longevious enough for archeology) > would decay fast enough to be useful here? The issue isn't just how long-lived an isotope is; it also matters whether uptake of the isotope (as a fraction of all isotopes of the element) is constant. The reason carbon-14 dating has worked well is that the C-14 production rate has been roughly constant for thousands of years. (In fact, there have been minor glitches in the rate due to disturbances in the earth's magnetic field, etc., but those are incremental effects.) In principle, one might use beryllium-7, which has a much shorter half life (53 days), if there was enough beryllium in the sample to be analyzable. (Remember, beryllium is EXTREMELY toxic.) However, beryllium-7 gets produced erratically (primarily through cosmic-ray interactions in the atmosphere, which are more or less time-independent, and atmospheric nuclear tests, which definitely are NOT time-independent) and doesn't get homogenized through "native" terrestrial beryllium. Consequently the rate of uptake of Be-7 per gram of beryllium isn't constant, and the technique wouldn't work. About the same reasoning more or less precludes use of any other radionuclide: if it's short-lived enough to be useful, about the only things that can make it near earth's surface are cosmic rays and nuclear explosions -- and the latter screw up production rates of the former in spectacular fashion. (Don't blame me -- I just work here.) Between this and the problem of getting the radionuclide mixed in with the stable isotopes, it just don't work. Incidentally, the REALLY bad news is that atmospheric testing (and maybe also Chernobyl to some fantastically tiny extent) also releases C-14 into the environment -- not a lot, but it doesn't take much. Consequently, C-14 dating of biological samples that were alive after August 1945 won't work either. The archaeologists of the year 6000 are going to have to think of some other dating technique. Life is hard. -------------------------------------------------------------- Bill Johnson Opinions? Who Los Alamos National Laboratory has opinions?