Download Free Experimental Investigations Of Tail Regeneration In The Lizard Anolis Carolinensis Book in PDF and EPUB Free Download. You can read online Experimental Investigations Of Tail Regeneration In The Lizard Anolis Carolinensis and write the review.

Well-established model systems exist in four out of the seven major classes of vertebrates. These include the mouse, chicken, frog and zebrafish. Noticeably missing from this list is a reptilian model organism for comparative studies between the vertebrates and for studies of biological processes unique to reptiles. To help fill in this gap the green anole lizard, Anolis carolinensis, is being adapted as a model organism. Despite the recent release of the complete genomic sequence of the A. carolinensis, the lizard lacks some resources to aid researchers in their studies. Particularly, the lack of transcriptomic resources for lizard has made it difficult to identify genes complete with alternative splice forms and untranslated regions (UTRs). As part of this work the genome annotation for A. carolinensis was improved through next generation sequencing and assembly of the transcriptomes from 14 different adult and embryonic tissues. This revised annotation of the lizard will improve comparative studies between vertebrates, as well as studies within A. carolinensis itself, by providing more accurate gene models, which provide the bases for molecular studies. To demonstrate the utility of the improved annotations and reptilian model organism, the developmental process of somitogenesis in the lizard was analyzed and compared with other vertebrates. This study identified several key features both divergent and convergent between the vertebrates, which was not previously known before analysis of a reptilian model organism. The improved genome annotations have also allowed for molecular studies of tail regeneration in the lizard. With the annotation of 3' UTR sequences and next generation sequencing, it is now possible to do expressional studies of miRNA and predict their mRNA target transcripts at genomic scale. Through next generation small RNA sequencing and subsequent analysis, several differentially expressed miRNAs were identified in the regenerating tail, suggesting miRNA may play a key role in regulating this process in lizards. Through miRNA target prediction several key biological pathways were identified as potentially under the regulation of miRNAs during tail regeneration. In total, this work has both helped advance A. carolinensis as model system and displayed the utility of a reptilian model system.
The present review covers a very neglected field in regeneration studies, namely, tissue and organ regeneration in reptiles, especially represented by the lizard model of regeneration. The term “regeneration” is intended here as “the ability of an adult organism to recover damaged or completely lost body parts or organs.” The process of recovery is further termed “restitutive regeneration” when the lost part is reformed and capable of performing the complete or partial physiological activity performed by the original, lost body part. Lizards represent the only amniotes that at the same time show successful organ regeneration, in the tail, and organ failure, in the limb (Marcucci 1930a, b; Simpson 1961, 1970, 1983). This condition offers a unique opportunity to study at the same time mechanisms that in different regions of the same animal control the success or failure of regeneration. The lizard model is usually neglected in the literature despite the fact that the lizard is an amniote with a basic histological structure similar to that of mammals, and it is therefore a better model than the salamander (an a- mniote) model to investigate regeneration issues.
Since its introduction to Florida, the brown anole, Anolis sagrei, has steadily expanded its range into that of its native congener in the southeastern United States, the green anole, A. carolinensis. Anolis sagrei achieves very high densities both in its native and invaded range and appears to impose population declines and shifts in the realized habitat niche of A. carolinensis. In order to investigate whether these effects arise prior to the adult age class in which they have previously been described, I studied the behavior of juvenile anoles at the individual, dyadic, and neighborhood levels. Contrary to some characterizations of adult microhabitat selection, distribution models of individual movement on laboratory thermal gradients indicate that juvenile A. carolinensis are likely to occupy warmer sites than A. sagrei, but with broad overlap in the full range of temperatures selected by these species. Staged dyadic encounters between socially naive juveniles of these species, however, suggest that intrinsic individual characteristics influencing dominance and behavioral exclusion in the youngest juvenile anoles favor A. carolinensis over A. sagrei. To confirm these observations and explore their consequences under conditions representative of natural juvenile assemblages, I compared the behavior and habitat use of A. carolinensis juveniles in single-species field enclosures with A. carolinensis and A. sagrei juveniles in two-species enclosures and described changes in the partitioning of space over the first weeks of life. Within the first week, thermal microhabitat partitioning was apparent and juvenile A. carolinensis in the presence of A. sagrei juveniles exhibited an upward shift in mean perch height similar to that seen in reproductive males following experimental imposition of sympatry in adults of these species. Despite the shift in structural habitat use of A. carolinensis juveniles in the presence of A. sagrei, there was no observed consequence of syntopy on growth rate or survival. This study suggests no immediate role of juvenile interactions on numerical declines in A. carolinensis in sympatry with A. sagrei, but does indicate that a more ontogenetically comprehensive approach is warranted in the characterization of niche differences and habitat partitioning.