----- Original Message ----- From: <pbs-request@lists.ibiblio.org> To: <pbs@lists.ibiblio.org> Sent: Tuesday, November 21, 2006 4:29 PM Subject: pbs Digest, Vol 46, Issue 26 > Send pbs mailing list submissions to > pbs@lists.ibiblio.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://www.pacificbulbsociety.org/list.php > or, via email, send a message with subject or body 'help' to > pbs-request@lists.ibiblio.org > > You can reach the person managing the list at > pbs-owner@lists.ibiblio.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of pbs digest..." > > > List-Post: <mailto:pbs@lists.ibiblio.org> > List-Archive: <http://www.pacificbulbsociety.org/pbslist/> > > Today's Topics: > > 1. Re: Virus (totototo@telus.net) > 2. Lilies & virus (John Bryan) > 3. Re: Lilies & virus (John T Lonsdale) > 4. Re: Lilies & virus (Alani Davis) > 5. Re: Lilies & virus (Jim McKenney) > 6. Re: Lilies & virus (John T Lonsdale) > 7. Clonal breakdown (John Bryan) > 8. Re: Clonal breakdown (Diane Whitehead) > 9. Re: Clonal breakdown (Boyce Tankersley) > 10. Re: Lilies & virus (eob@vqme.com) > 11. Re: Neomarica - more (piaba) > 12. Re: Clonal breakdown (Jim McKenney) > 13. FW: Clonal breakdown (John T Lonsdale) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Tue, 21 Nov 2006 10:29:34 -0800 > From: totototo@telus.net > Subject: Re: [pbs] Virus > To: pbs@lists.ibiblio.org > Message-ID: <20061121182902.73KSKR1U83@priv-edmwaa05.telusplanet.net> > Content-Type: text/plain; charset=US-ASCII > > On 1 Jan 90, at 0:21, John Bryan wrote: > >> ...Growers in the Netherlands are very conscious of the need to >> sell only the best possible stock. > > I nearly choked on my morning bagel when I read that. Maybe they're > *conscious* of this need, but Dutch growers don't seem to act on that > consciousness. The Dutch bulb trade is notorious for mislabelling > what they send out, and it's well known that some types of bulbs from > Dutch sources are virtually always virused, lilies being the classic > example. I could mention the horrible virused form of Crocus > kotschyanus, but I won't. > > The mislabelling is insidious because they are generally careful to > substitute something with approximately the same look. Out of some > bluish Crocus biflorus cultivar? Just grab a bunch of C. > tommasinianus; no one will ever notice the difference. It is no > accident and esp. now when the bulbs are all prepackaged, it isn't > due to customers mixing the contents of the bins. That's the excuse I > used to get when I complained about misnamed bulbs! > > And some of the other "bulbs" one buys are diseased in other ways: > one friend with access to the necessary equipment determined that a > dahlia from Dutch sources was loaded with nematodes. > > It may be that you are distinguishing "growers" from "wholesalers" > and "distributors", but a man is known by the company he keeps. The > entire Dutch bulb trade is, I am sorry to say, unreliable and has > known for its failings since at least 1950 when E. B. Anderson > inveighed against mislabelled Dutch bulbs. > > Simply put, it appears that the Dutch bulb industry is long on profit > motive at the expense of ordinary everyday ethics and honesty. Their > long history of selling wild-collected bulbs, with the end result of > near extinction of many species, is just another example. > > > -- > Rodger Whitlock > Victoria, British Columbia, Canada > Maritime Zone 8, a cool Mediterranean climate > > on beautiful Vancouver Island > > > ------------------------------ > > Message: 2 > Date: Mon, 01 Jan 1990 00:38:06 -0800 > From: John Bryan <johnbryan@worldnet.att.net> > Subject: [pbs] Lilies & virus > To: pbs@lists.ibiblio.org > Message-ID: <259F16EE.728A69A6@worldnet.att.net> > Content-Type: text/plain; charset=us-ascii > > Way back in the 60's, the lily hybrid Enchantment, introduced by Jan de > Graaff's Oregon Bulb Farms, began to loose the size of flowers and the > bud count. Many acres of this hybrid had been grown for a great number > of years. It was decided to propagate, by tissue culture, a new stock. > Enchantment was, the first lily to receive a Patent, being grow widely > for cut flower production as well as a garden plant and we exported many > thousands to the Netherlands. It is to be noted that the plants did not > show signs of virus, just the flower size and count diminished. This was > thought to be a clonal breakdown, not an unusual occurrence and I think > this was a correct diagnosis. > > The result of the tissue culture was the new stock, so propagated, > regained the flower size and bud count of previous years. Thus it is not > only virus that causes such problems, but clonal breakdown is another > factor of a decline of a variety/culivar. I suppose Enchantment is still > being grown but has been superseded by newer hybrids, but the bloodline > of this great Asiatic lilly can still be seen in progeny, for example > the black tips of the buds etc. > > This might be of interest, the point being decline of a plant is not > always due to a virus, but continued propagation by vegetative means can > also cause problems. Cheers, John E. Bryan > > > ------------------------------ > > Message: 3 > Date: Tue, 21 Nov 2006 14:26:18 -0500 > From: "John T Lonsdale" <john@johnlonsdale.net> > Subject: Re: [pbs] Lilies & virus > To: "'Pacific Bulb Society'" <pbs@lists.ibiblio.org> > Message-ID: <009301c70da2$eb9fa600$6601a8c0@XPS400> > Content-Type: text/plain; charset=us-ascii > > John Bryan, > > Can you please explain what you mean by 'clonal breakdown'? How does TC > of > a lily suffering from 'clonal breakdown' fix this? > > Thanks. > > > John T Lonsdale PhD > 407 Edgewood Drive, > Exton, Pennsylvania 19341, USA > > Home: 610 594 9232 > Cell: 484 678 9856 > Fax: 801 327 1266 > > Visit "Edgewood" - The Lonsdale Garden at http://www.edgewoodgardens.net/ > > USDA Zone 6b > > > > > ------------------------------ > > Message: 4 > Date: Tue, 21 Nov 2006 14:41:54 -0500 > From: "Alani Davis" <adavis@ecoresource.com> > Subject: Re: [pbs] Lilies & virus > To: <john@johnlonsdale.net>, "'Pacific Bulb Society'" > <pbs@lists.ibiblio.org> > Message-ID: <006801c70da5$19ffd4f0$0305a8c0@crinum> > Content-Type: text/plain; charset="us-ascii" > > I am curious about this as well. I have heard this used many times as a > reason for decline of a variety through clones do to excessive asexual > reproduction, but would be the mechanism for this "decline"? How can > genetic > "vigor" be "lost"? How can one "know" it is clonal breakdown and not > environmental or pathanogenic? > > Alani Davis > Tallahassee, Florida > > > -----Original Message----- > From: pbs-bounces@lists.ibiblio.org [mailto:pbs-bounces@lists.ibiblio.org] > On Behalf Of John T Lonsdale > Sent: Tuesday, November 21, 2006 2:26 PM > To: 'Pacific Bulb Society' > Subject: Re: [pbs] Lilies & virus > > John Bryan, > > Can you please explain what you mean by 'clonal breakdown'? How does TC > of > a lily suffering from 'clonal breakdown' fix this? > > Thanks. > > > John T Lonsdale PhD > 407 Edgewood Drive, > Exton, Pennsylvania 19341, USA > > Home: 610 594 9232 > Cell: 484 678 9856 > Fax: 801 327 1266 > > Visit "Edgewood" - The Lonsdale Garden at http://www.edgewoodgardens.net/ > > USDA Zone 6b > > > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://www.pacificbulbsociety.org/list.php > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > ------------------------------ > > Message: 5 > Date: Tue, 21 Nov 2006 14:45:32 -0500 > From: "Jim McKenney" <jimmckenney@jimmckenney.com> > Subject: Re: [pbs] Lilies & virus > To: "'Pacific Bulb Society'" <pbs@lists.ibiblio.org> > Message-ID: <000c01c70da5$9b4b8090$2f01a8c0@Library> > Content-Type: text/plain; charset="us-ascii" > > While we're waiting for John Bryan's response on this, I'll add this. What > John Bryan called clonal breakdown might be what I think of as clonal > drift. > > > Clonally propagated material varies over time, and the amount of variation > is probably proportional to the number of replications involved. > > To keep a clonally propagated product within the expectations of > consumers, > it's necessary periodically to reselect typical material on which to base > future cloning. > > This clonal drift is not necessarily a disadvantage. Many of the tulips of > the double early division are said to be somatic mutations of the tulip > Murillo, which itself is a somatic mutation of a single early tulip. So > where there was originally one product, there are now many, all pieces of > one original seedling. > > > Jim McKenney > jimmckenney@jimmckenney.com > Montgomery County, Maryland, USA, USDA zone 7 > My Virtual Maryland Garden http://www.jimmckenney.com/ > > Webmaster Potomac Valley Chapter, NARGS > Editor PVC Bulletin http://www.pvcnargs.org/ > > Webmaster Potomac Lily Society http://www.potomaclilysociety.org/ > > > > > > > > > > ------------------------------ > > Message: 6 > Date: Tue, 21 Nov 2006 14:46:59 -0500 > From: "John T Lonsdale" <john@johnlonsdale.net> > Subject: Re: [pbs] Lilies & virus > To: "'Pacific Bulb Society'" <pbs@lists.ibiblio.org> > Message-ID: <009801c70da5$cf72ca40$6601a8c0@XPS400> > Content-Type: text/plain; charset=us-ascii > > John Bryan wrote - "It is to be noted that the plants did not show signs > of > virus, just the flower size and count diminished." > > This is rather like saying the patient didn't show signs of HIV infection, > his CD4 cell count just plummeted; his viral load went through the roof, > he > got a bunch of opportunistic infections and suffered from Kaposi's > sarcoma. > > If reduced flower size and count aren't classic signs of viral infection > in > plants then I don't know what is. > > Perhaps you mean that the lily didn't have a bunch of yellow streaks in > the > leaves? > > Thanks, > > John T Lonsdale PhD > 407 Edgewood Drive, > Exton, Pennsylvania 19341, USA > > Home: 610 594 9232 > Cell: 484 678 9856 > Fax: 801 327 1266 > > Visit "Edgewood" - The Lonsdale Garden at http://www.edgewoodgardens.net/ > > USDA Zone 6b > > > > > ------------------------------ > > Message: 7 > Date: Mon, 01 Jan 1990 03:08:44 -0800 > From: John Bryan <johnbryan@worldnet.att.net> > Subject: [pbs] Clonal breakdown > To: pbs@lists.ibiblio.org > Message-ID: <259F3A3C.2871B91C@worldnet.att.net> > Content-Type: text/plain; charset=us-ascii > > Dear All: > > Hybrid vigor, while evident in plants raised from seed, does not last > for ever if continued asexual reproduction of a plant is continued over > many years. The classic example perhaps is to be found in the strawberry > Royal Sovereign, which just failed after many years. At one time it was > far ahead of other cultivars, but then lost many of the qualities for > which it was renowned. To my knowledge such loss of desired qualities > were simply lost due to the continued asexual propagation. Just what > happens when such does take place I do not know, but such has been > refereed to as Clonal Breakdown. Possibly the desired arrangement and > composition of the cells in the plant(s) was changed. > > John Lonsdale asked how TC fix this. Again a definitive answer, to my > knowledge, as not been determined, but it does work. Perhaps this method > of propagation is taking advantage of cells that are, for want of a > better explanation, stronger and closer to the original cells of the > first crosses and better replicas of cells carrying the desired > qualities. > > I should have mentioned the plants of Enchantment did not show any > visible signs of virus, to all intents and purposes the plants appeared > to be the same, except for size of flowers and bud count. > > Here it must be stated, those plants used for asexual propagation, were > selected in the field, the strongest, those with good flower size and > bud count were those selected and these plants showed no color variation > in the foliage at all. Selecting those plants that are the most vigorous > is an ongoing practice of good growers. When growing many hundreds of > Dahlias, I used to tag those tubers for propagation in the field and > they were lifted first prior to the lifting of others. > > John Londsale asks if reduced flower size and count are not classic > signs of viral infection, perhaps they are, but are not such accompanied > by other signs as well, such as changes in the foliage? Does this mean > such changes as clonal breakdown do not exist? When examined in the 60's > for virus, using the techniques available at that time, no virus was > found. > > Rodger Whitlock almost choked on his bagel, when he read my comments > regarding growers in the Netherlands, if you have found such poor > practices s you describe, I hope you have reported such to all > authorities who could challenge the practices and do something about it. > Is this perhaps a reason why such strict regulations are now in place > with importation of plants from overseas and which are decried by so > many? Perhaps the USDA are correct! In any profession there are rogues, > but firms such as Hoog and Dix, to mention but one, strive to maintain > the highest standards in nomenclature and health of the products they > sell. To label all growers as being, in effect, dishonest is not only > untrue but, in my opinion a libelous statement. such as Dahlias loaded > with nematodes. To which grower(s) are you referring? Have you reported > them to authorities? If not, why not? As to the selling of wild selected > bulbs, I presume you are aware of the rule governing such and these > rules are and have been imposed by the authorities in the Netherlands. > > Alani Davis asked how can one know if it is clonal breakdown and not > environmental or pathanogenic? I do not know, but the term clonal > breakdown was the term we used, other factors may well have played a > part, but let us not blame virus for all such occurrences, especially > after tests were made to see if virus was present. But as I mentioned, > this was way back in the 60's and more recent procedures might be able > to answer this question. > > The posting of Jim McKenney was interesting. I had not heard the term > Clonal Drift before, but obviously this must be the same. jim, as > mentioned above, steps were taken to keep the product within the > expectations of the consumer. this is why that, during the last years I > was with Oregon Bulb Farms, we were relying on 'strains' as such, being > seed of crosses between established clones as were the seed parents, had > vigor and the variation in height, color, size and number of flowers > were between very narrow limits. Black Dragon Strain took the place of > the clone Black Dragon, and Golden Splendor Strain took the place of the > clone of the same name, etc. Jim, could you explain somatic mutations? > How do such differ from other mutations/ > Cheers and Happy Thanksgiving to all I hope your turkeys are tasty, and > good eating and would there be clonal breakdown in such birds brought > about by inbreeding? > > > ------------------------------ > > Message: 8 > Date: Tue, 21 Nov 2006 13:38:02 -0800 > From: Diane Whitehead <voltaire@islandnet.com> > Subject: Re: [pbs] Clonal breakdown > To: Pacific Bulb Society <pbs@lists.ibiblio.org> > Message-ID: <CA623268-73B5-45D7-AE3D-16753CFFC775@islandnet.com> > Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed > > > I have read articles on human aging that state that cells can > duplicate themselves only a certain number of times. I'm not sure > what happens when this point is reached: do they stop? do they > accumulate mutations? > > Could this limit on cell duplication also be present in plants? > > Diane Whitehead > > > ------------------------------ > > Message: 9 > Date: Tue, 21 Nov 2006 15:43:12 -0600 > From: "Boyce Tankersley" <btankers@chicagobotanic.org> > Subject: Re: [pbs] Clonal breakdown > To: "Pacific Bulb Society" <pbs@lists.ibiblio.org> > Message-ID: > <52857FDB394B7E45BA1F2E60D7313E2A059CC906@cbgmail.chicagobotanic.org> > Content-Type: text/plain; charset="us-ascii" > > This information is from my memory so subject to error. I believe I read > the teliospores shorten everytime a cell divides. After a number of > years they are, in effect, down to the bare bones. It is at this stage > that decreases in vigor and other characteristics are noticeable. > > Boyce Tankersley > btankers@chicagobotanic.org > > -----Original Message----- > From: pbs-bounces@lists.ibiblio.org > [mailto:pbs-bounces@lists.ibiblio.org] On Behalf Of Diane Whitehead > Sent: Tuesday, November 21, 2006 3:38 PM > To: Pacific Bulb Society > Subject: Re: [pbs] Clonal breakdown > > > I have read articles on human aging that state that cells can > duplicate themselves only a certain number of times. I'm not sure > what happens when this point is reached: do they stop? do they > accumulate mutations? > > Could this limit on cell duplication also be present in plants? > > Diane Whitehead > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://www.pacificbulbsociety.org/list.php > > > ------------------------------ > > Message: 10 > Date: Tue, 21 Nov 2006 15:58:15 -0500 (EST) > From: eob@vqme.com > Subject: Re: [pbs] Lilies & virus > To: "Pacific Bulb Society" <pbs@lists.ibiblio.org> > Message-ID: <1727.4.136.141.181.1164142695.squirrel@http://www.vqme.com/> > Content-Type: text/plain; charset=iso-8859-1 > > "Clonal breakdown" is an interesting term, and I do know that continued > propagation of many plants can lead to decline in vigor, etc., but what > does the term actually refer to? If it is actually a change in the > genetics of the plant, then no amount of tissue culturing and "cleaning > up" of the clone is going to change the genetics back to the original. > > Does anyone know what the theory is re what is actually taking place if, > in fact, it is not removing virus. For that matter if the virus has been > incorporated into the genes (as often happens), then how do they clean > that up by tissue culture? Or, are the answers to these questions to > technical for this list? > > Ernie O'Byrne > Eugene, Oregon USA > > >> Sender Allowed >> >> Way back in the 60's, the lily hybrid Enchantment, introduced by Jan de >> Graaff's Oregon Bulb Farms, began to loose the size of flowers and the >> bud count. <snip> This was >> thought to be a clonal breakdown, not an unusual occurrence and I think >> this was a correct diagnosis. >> > <snip> >> >> This might be of interest, the point being decline of a plant is not >> always due to a virus, but continued propagation by vegetative means can >> also cause problems. Cheers, John E. Bryan >> >> > > > > > ------------------------------ > > Message: 11 > Date: Tue, 21 Nov 2006 14:17:12 -0800 (PST) > From: piaba <piabinha@yahoo.com> > Subject: Re: [pbs] Neomarica - more > To: Pacific Bulb Society <pbs@lists.ibiblio.org> > Message-ID: <20061121221713.96187.qmail@web51902.mail.yahoo.com> > Content-Type: text/plain; charset=iso-8859-1 > > i was traveling with mauro in 2001 when we found and > photographed that pic of N. glauca on the website. > flowers are smaller than other Neo. in that trip, > there were also 2 other weird irids we found in MG > state, unfort. neither one in bloom. one had > succulent leaves that were curvy (it could be the one > that he has as Pseudo. recurvata on his website), and > the other one had very thin and long but cylindrical > leaves. seeds of this last one germinated for me as > very thin tufts of grass but none survived to > adulthood. > > actually, when i think of it, we found so many weird > plants in the "campos rupestres" of MG, incl. some > weird yellow-flower bulb in the Rapateaceae family, > Sysirinchiums, Zephyranthes, crazy Melastomataceae > (not bulbs of course),and wonderful tuberous > APocynaceae with gorgeous flowers. > > ========= > tsuh yang > > --- Lee Poulsen <wpoulsen@pacbell.net> wrote: >> Mauro Peixoto has photos of the following species >> (as well as two >> very nice looking unnamed species): >> Neomarica glauca >> > http://mpeixoto.sites.uol.com.br/iridaceae/… > > > > > ____________________________________________________________________________________ > Sponsored Link > > Mortgage rates near 39yr lows. $420k for $1,399/mo. > Calculate new payment! http://www.lowermybills.com/lre/ > > > ------------------------------ > > Message: 12 > Date: Tue, 21 Nov 2006 17:18:20 -0500 > From: "Jim McKenney" <jimmckenney@jimmckenney.com> > Subject: Re: [pbs] Clonal breakdown > To: "'Pacific Bulb Society'" <pbs@lists.ibiblio.org> > Message-ID: <001501c70dba$f3ed93e0$2f01a8c0@Library> > Content-Type: text/plain; charset="us-ascii" > > John Bryan asked "Jim, could you explain somatic mutations? " > > I'm glad you asked this, John because it gives me the chance to tie > together > some disparate threads in my past postings. > > Somatic mutations are nothing more than what gardeners for centuries have > called sports. In the old days, with no knowledge of genetics and cell > division, this process must have seemed very mysterious. > > Somatic mutations are also the basis for my repeated assertion that the > elements which make up a clone are not necessarily genetically uniform. > > There are many ways of classifying the cells in an organism. One way is to > make the distinction between germinal cells (those which produce gametes, > reproductive cells) and the cells which make up most of the body of the > organism in question (somatic cells). > > In plants, somatic cells containing mutations might survive and continue > to > divide. Not only that, but if the plant in question is one being subjected > to intense asexual reproduction, there is always the possibility that > entities will result which contain only the mutated cells or a majority of > mutated cells. If the mutation in question is one which results in a > grossly > visible difference, then the gardener calls it a sport and treats it as a > new variety. > > On the other hand, when mutations occur in the germinal cells which > produce > gametes (eggs, sperm), the results are not likely to be visible in the > organism; however, because these cells produce gametes, such mutations can > be passed on to the progeny which result from sexual reproduction. > > That is why if you hybridize with plants whose distinctive characteristics > are the result of somatic mutations, any progeny which result will almost > certainly show the pre-somatic mutation characteristics. For instance, if > you cross parrot tulips with parrot tulips, chances are the resulting > progeny will be ordinary single tulips with not a parrot tulip among them. > > On the other hand, if you have a plant in which a mutation has occurred in > the germinal cells, there is a good chance that such a mutation will be > passed on to the progeny and, subject to the usual rules of genetic > expression, be apparent in such progeny. A simple example: plants which > typically produce red flowers often have yellow variants which are the > result of a relatively simple mutation in the germinal cells. If you cross > two such yellow flowered plants, chances are good that you will get plenty > of yellow flowered progeny rather than the typical red (assuming the > yellow > is a simple recessive to the red). > > That's it in a nutshell. For those who want more information, go to > Google. > > Jim McKenney > jimmckenney@jimmckenney.com > Montgomery County, Maryland, USA, USDA zone 7 > My Virtual Maryland Garden http://www.jimmckenney.com/ > > Webmaster Potomac Valley Chapter, NARGS > Editor PVC Bulletin http://www.pvcnargs.org/ > > Webmaster Potomac Lily Society http://www.potomaclilysociety.org/ > > > > > > > > > > > ------------------------------ > > Message: 13 > Date: Tue, 21 Nov 2006 17:29:09 -0500 > From: "John T Lonsdale" <john@johnlonsdale.net> > Subject: [pbs] FW: Clonal breakdown > To: "'Pacific Bulb Society'" <pbs@lists.ibiblio.org> > Message-ID: <00c201c70dbc$76e39eb0$6601a8c0@XPS400> > Content-Type: text/plain; charset=us-ascii > > When an organism or cell is propagated asexually for any period of time it > inevitably picks up somatic mutations. These are mutations in genes in > cells other than germline cells and they are not passed on by sexual > reproduction. These mutations may be silent (not obvious) or cause a > change in the phenotype (the organism looks or behaves differently). > Somatic mutations may cause cancer or variegation, for example. Many > cancers are the result of the acquisition of many somatic mutations, > each allowing the cell to escape from normal control mechanisms. I can > only assume that John Bryan's 'clonal breakdown' is the actually > accumulation of multiple somatic mutations that cause the desirable > features of a plant to be lost, or undesirable ones gained. 'Clonal > breakdown' cannot be fixed. In the case cited by JB he selected a > single individual from the population with desirable (or in reality > fewer undesirable) characteristics, put it into TC and propagated it > thereafter. It will still have carried forward all the somatic > mutations it had previously acquired, and would continue to acquire new > ones. > > Clonal drift is the same process as above. It is a problem in many > areas. For example human cells passaged in culture many times will > sooner rather than later start behaving differently to the cells that > were originally isolated. This has a big impact if those cultured cells > are to be used in research because they no longer are representative of > the cells that would be found in the body. > > Continued asexual reproduction, per se, does not cause a 'loss of > vigor', that is pure bunkum! > > It is wrong to think that all viruses cause leaf streaking - infection > can have many different symptoms or none at all that are visible. > Humans carry many viruses that are silent for some, most or all of the > time. > > One of the aging processes in cells other than stem cells is (as Boyce > said) a gradual shortening of the telomeres (the caps at the end of > chromosomes). Once they get past a certain point the cell detects this > and can become senescent or enters a pathway of programmed cell death > (apoptosis). In the devastating disease Progeria, which causes > premature aging in humans, the telomeres become prematurely shortened. > > Thanks, > > J. > > > > > ------------------------------ > > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://www.pacificbulbsociety.org/list.php > > > End of pbs Digest, Vol 46, Issue 26 > *********************************** >