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Variation and Evolution of Genome Size in Gymnosperms
| Content Provider | Scilit |
|---|---|
| Author | Ohri, Deepak |
| Copyright Year | 2021 |
| Abstract | Gymnosperms show a significantly higher mean (1C=18.16, 1Cx=16.80) and a narrow range (16.89-fold) of genome sizes as compared with angiosperms. Among the 12 families the largest ranges of 1C values is shown by Ephedraceae (4.73-fold) and Cupressaceae (4.45-fold) which are partly due to polyploidy as 1Cx values vary 2.41 and 1.37-fold respectively. In rest of the families which have only diploid taxa the range of 1C values is from 1.18-fold (Cycadaeae) to 4.36-fold (Podocarpaceae). The question is how gymnosperms acquired such big genome sizes despite the rarity of recent instances of polyploidy. A general survey of different families and genera shows that gymnosperms have experienced both increase and decrease in their genome size during evolution. Various genomic components which have accounted for these large genomes have been discussed. The major contributors are the transposable elements particularly LTR-retrotransposons comprising of Ty3gypsy, Ty1copia and gymny superfamilies which are most widespread. The genomes of gymnosperms have been acquiring diverse LTR-RTs in their long evolution in the absence of any efficient mechanism of their elimination. The epigenetic machinery which silences these large tracts of repeat sequences into the stretches of heterochromatin and the adaptive value of these silenced repeat sequences need further investigation. |
| Related Links | https://www.sciendo.com/pdf/10.2478/sg-2021-0013 |
| Ending Page | 169 |
| Page Count | 14 |
| Starting Page | 156 |
| e-ISSN | 25098934 |
| DOI | 10.2478/sg-2021-0013 |
| Journal | Silvae Genetica |
| Issue Number | 1 |
| Volume Number | 70 |
| Language | English |
| Publisher | Walter de Gruyter GmbH |
| Publisher Date | 2021-01-01 |
| Access Restriction | Open |
| Subject Keyword | Silvae Genetica Evolutionary Biology Evolution Gymnosperms Fold 1cx Silenced Repeat Ltr Genome Sizes Epigenetic Adaptive Journal: Silvae Genetica, Issue- 3 |
| Content Type | Text |
| Resource Type | Article |
