fig2 a and 2b shows a comparison of a gel obtained from telomere measurement using standard trf analysis ( fig2 a ) and a scan of a blot obtained using the slot - blotting method described above ( fig2 b ). fig3 shows tables displaying the results obtained using the slot - blotting method . these tables show that telomere length and t2ag3 ( ttaggg ) signal intensity decrease with increased population doubling levels ( pdl ), and show that t2ag3 signal intensity increases with telomere length . these results are shown for both bj cells ( human foreskin fibroblast ) and for s2c cells ( human skin fibroblast ). these cells , are publicly available through the american type culture collection ( atcc ). however , these exemplified cells are not essential to the method , as any cell type could be used with this method . in addition , these tables show the increase in t2ag3 signal intensity with increase in concentration of pblrep4 . pblrep4 is a plasmid , publicly available through atcc , which comprises 100 of the telomere repeat sequences 5 &# 39 ;- ttaggg - 3 &# 39 ; inserted into the ecori site of the stratagene vector pbluescriptiisk +. as shown in this figure , this plasmid can be used to produce a standard curve by providing known amounts of telomere repeat sequence . column 1 shows the population doubling level ( pdl ) for the bj cells . column 2 shows the t2ag3 intensity for bj cell telomeres hybridized to telomere probes by means of the slot blotting method . column 3 shows the average telomere length of the bj cells , measured by trf analysis . column 4 shows the population doubling level ( pdl ) for the s2c cells . column 5 shows the t2ag3 intensity for s2c cell telomeres hybridized to telomere probes by means of the slot blotting method . column 6 shows the average telomere length of the s2c cells , measured by trf analysis . column 7 shows the amount of t2ag3 repeat sequence ( in pmol ) in the pblrep4 standards . column 8 shows the t2ag3 intensity for pblrep4 hybridized to telomere probes by means of the slot blotting method . fig4 - 6 show graphic representation of results obtained using the slot - blotting method . fig4 represents the standard curve of pblrep4 , and shows that the signal increases in a linear manner with increased concentration of pblrep4 ( t2ag3 ). fig5 and 6 show that t2ag3 intensity decreases with increased pdl in bj cells and s2c cells . this is consistent with the decrease in telomere length seen with increased pdl in these cells ( see fig3 ). fig7 shows a scan of a 96 - well plate in which dna samples were probed with a telomere - specific riboprobe as described above . fig8 - 9 show graphical representations of the results obtained when different amounts of dna were probed with the telomere - specific probe . these graphs show that increased signal was produced with increased amount of dna . fig1 - 12 show results obtained using the telomere probe method described above to compare telomere length of samples . fig1 a and 10b show the placement of samples ( as described below in example 2 ) in a 96 - well plate , and the scan of these samples after hybridization with the riboprobe . fig1 is a table of the results of the scan , and the trf lengths of the samples , measured by conventional trf analysis . this figure shows that the signal intensity was higher in the samples with longer trfs , and that this was consistent for all concentrations . fig1 shows a graphic representation of these results . the following are examples of specific aspects of the invention to illustrate this invention to those in the art . these examples are not limiting of the invention , but provide an indication of specific methodology useful in practice of the invention . the slot - blotting method was carried out as described below to determine telomere length of samples . these cells and plasmids are not limiting in this invention . 1 . 5 μg of total genomic dna from bj cells ( human foreskin fibroblast ) and from s2c ( human skin fibroblast ) at different population doubling levels (&# 34 ; pdl &# 34 ;) was digested with both ecori and hindiii overnight . 1 . 25 μg of plasmid pblrep4 ( which is equivalent to 52 . 6 pmol of t2ag3 repeat ) was digested with xbai . this was used as a standard . 1 . 5 μg of lambda phage dna was digested with both sau3a and hindiii , to be used as a negative control . the digested dna was purified by phenol / chloroform extraction followed by ethanol precipitation , then was resuspended in 100 μl of 1 × te buffer . 200 μl of 5 × ssc was added to bring the volume to 300 μl , and the solution was mixed thoroughly . a schleicher & amp ; schuell minifold ii ™ apparatus was used to do the slot blotting . the blotting paper and nitrocellulose paper was wet with 5 × ssc , and each slot was rinsed with 300 μl 5 × ssc . the digested dna samples were then loaded onto the designated slots . to generate a standard curve on the blot , the digested plasmid pblrep4 was diluted at a serial ratio , and 0 . 009375 μg , 0 . 00625 μg , 0 . 003125 μg , and 0 . 0015625 μg was loaded onto separate slots . a vacuum was used to filter all liquid through the blot , retaining the dna on the blot . the nitrocellulose was then removed and placed on a piece of 3 mm paper and air dried for 30 minutes . the dna was denatured by placing the blot on a stack of 3 mm paper soaked with 0 . 5n naoh + 1 . 5m nacl for 30 minutes . the dna was then neutralized by placing the blot on 3 mm paper soaked with 0 . 5 m tris at ph 7 . 4 , 1 . 5m nacl for 30 minutes . the dna was cross - inked to the blot with uv stratalinker 1800 ™ ( stratagene ). the blot was prehybridized with prehybridization buffer ( 15 ml of 5 × ssc , 5 × denhardt &# 39 ; s solution , 0 . 02m phosphate ph 6 . 5 , 0 . 1 mg / ml salmon sperm dna , 0 . 5 % sds , 50 % formamide ) for 2 hours . the blot was then hybridized with 15 ml prehybridization buffer plus 32 p labeled t2ag3 18 mer probe ( 1 million cpm / ml ), and incubated overnight at 37 ° c . the blot was washed with 500 ml 1 × ssc , 0 . 1 % sds once for 10 minutes at room temperature , then twice with 500 ml 0 . 1 × ssc , 0 . 1 % sds at 37 ° c . for 20 minutes . the blot was exposed in a phosphoimager ™ detector ( molecular dynamics ) overnight . the intensity of the hybridization was then analyzed . the signal intensity of t2ag3 hybridization in cells of different pdl was converted to a relative number that reflected the average length of telomeres according to the standard curve ( pblrep4 ). the slot blotting method showed the decrease in average telomere length with increased pdl . these results are consistent with the trf values determined by conventional methods . these results are shown in fig3 - 6 . the following is a description of a telomerespecific probe method , as described above , which can be used to measure telomere length . 2 six - well plates of 293 cells ( available through atcc ) at 100 , 000 / well and 1 six - well plate of 293 cells at 75 , 000 / well were used . the wells of the plates were washed twice with cold 1 × pbs buffer . 1 . 5 ml extraction buffer ( 10 mm tris , ph 8 . 0 , 0 . 1m edta , ph 8 . 0 , 0 . 1m nacl , 0 . 5 % sds , 100 μg / ml proteinase k ) was added to each well , and the samples were incubated at 50 ° c . for 3 - 16 hours , adding an additional dose of proteinase k after 1 hour . other extraction steps , e . g ., digesting with ecori / hindii and / or phenol : etoh extraction could also be used . 15 μl / well rnase , dnase - free , was added , and samples were incubated for 1 hour . cells were scraped and transferred to tubes . the samples were then heated at 65 ° c . for 10 - 20 minutes . the dna was removed with a glass pasteur pipet , and resuspended in 100 μl te buffer . 150 μl , 75 μl , 37 . 5 μl , and 18 . 75 μl , of the resuspended dna was spotted into 96 - well u - bottom plates . 160μl 0 . 5m naoh / 12 . 5 mm edta was added , and the contents were transferred to 96 - well filter plates . the filters were vacuumed , adding 160 μl 0 . 4m naoh , then washed in 2 × ssc and laid flat to dry . the filters were then hybridized with 50μl 32 p - upt labeled riboprobe ( comprising repeats of the sequence 5 &# 39 ;- ccctaa - 3 &# 39 ;, as discussed above ) overnight at 65 ° c . the filters were washed in 1 × ssc / 0 . 1 % sds 4 - 5 ×, and were exposed for at least 1 hour in a phosphoimager ™ ( molecualar dynamics ) cassette and scanned . fig8 - 9 show the results of a method as described above . these figures show that the signal increases with the amount of dna . using a method as described above , samples of known dna concentrations ( ovcar 4 , ovar 3 , ovar 5 , ovar 8 , and sk - ov - 3 , as shown in fig1 and 11 ) were analyzed to determine whether this method could be used to detect relative differences in telomere length . telomere lengths of these samples were measured using mean trf analysis , as discussed above . fig1 - 12 show that signal increased relative to telomere length . for example , sk - ov - 3 cells , had the highest trf of the samples ( 10 . 69 kb ) and also had the strongest signal at each concentration . the foregoing examples describe various aspects of the invention . the examples are not intended to provide an exhaustive description of the many different embodiments of the invention encompassed by the following claims .