Globin-intron Sequences Imply Molecular Relationships Between the Galapagos Giant Tortoise and the Aldabra Giant Tortoise

A novel molecular analysis of globin-intron sequences from the Galapagos giant tortoise (Geochelone nigra), Aldabra giant tortoise (G. gigantea), and Chaco tortoise (G. chilensis) supports their divergence approximately 15-21 million years ago, aligning with prior cDNA-based estimates. However, intron nucleotide sequences reveal unresolved ancestral relationships among the three species due to shared genetic traits, including an abnormal GC dinucleotide at a splicing site in αD globins—a feature common across all Geochelone tortoises—and a unique repeated sequence (5'-GCCCCGCGCCCCGC-3') exclusive to G. nigra's A globin gene, distinguishing it from its relatives.

Shishikura, F. (2013). Globin-intron Sequences Imply Molecular Relationships Between the Galapagos Giant Tortoise and the Aldabra Giant Tortoise. Journal of Nihon University Medical Association, 72(5), 326–334. https://doi.org/10.4264/numa.72.5_326