2002 Volume 67 Issue 2 Pages 185-190
The intolerance exhibited to loss of DNA end sequences beyond a threshold, points to the existence of a requirement of a minimum telomere size per chromosome end. The relation of chromosome length to telomere length was studied in the genus Pennisetum. Species differing in chromosome length were analysed for telomere length. For a relative comparison, the extent of intra specific variation in telomere length was studied in the cultivated species of Pennisetum-P. glaucum (L.) R. Br. (pearl millet) using 8 inbred lines. Average telomere length (ATL) was estimated by densitometric measurement of the hybridization signal in the autoradiograms made from Southern blots of Hae III digested DNA samples probed with the plant telomere repeat sequence (5′-TTTAGGG-3′)4. The significance of the differences in ATL values in the plants analysed was determined by ANOVA and ‘t’ test. P. orientale, the species with very short chromosomes also had very short telomeres (ATL ca. 10kb). The ATL in the other species with much longer chromosomes than P. orientale was much higher-ranging between ca. 17 to ca. 24kb. Significant differences in ATL were observed among the inbreds of P. glaucum. One of the P. glaucum inbreds had a very high ATL value of ca. 41kb. The wild species with small differences in chromosome length did not have a significant difference in ATL values.
