NEWSLINE PAPER,- While mankind may differ from others rationally, one common feature to animals is the tail; human tail is absent in most vertebrates. For two and a half years' duration of this absence, this topic has often been the subject of rumination.
A tail is an accessory to the body of animals that serves to balance the body, helps in pushing, could be used to communicate, and fend of bites from insects. Nevertheless, among the élite creatures and the closest primate relatives of ours – great apes, this happened as long ago as twenty-five million years ago, which may be associated with the period when we split from the old world monkeys. These losses can be ascribed to the emergence of bipedalism in our species, however the genetic reasons that caused our hemispherelessness stayed unknown till recently.
Nowadays, geneticists have come to the conclusion that tail loss in humans has been caused by a small segment of genetic data, which is overly present in our genome and had been considered a span of ‘junk DNA’ due to its non-genetic function. These sequences of RNA, known as ALUs, serve to regulate tail length transcription via TBXT gene. Particularly, Alu is an “intruder gene”, giving such an opportunity to change in its location in the genome and mutations.
During the course of time someday ago Alu element AluY stuck fast to the TBXT gene of an ancestor of Hominoidia (great apes and humans). The sequencing and alignment of AluY elements in six hominoid species and fifteen non-hominoid primates were conducted. This course of the study revealed the presence of AluY only in hominoid genomes. It should be noted that the study has also successfully tested the changes in the Alu insertions in TBXT genes of genetically modified mice, which showed that this resulted in variable tail lengths.
This hypothesis was explored after many others have been brought up in the attempt to explain why primates/hominoids became tail-less, and most commonly, through the connection of taillessness to upright and parallel walking/bipedalism. nevertheless, the exact mode or reason of this genetic absence in humans and great apes was still unclear. This withholding becomes the primary candidate for the genetic mechanism responsible for the loss of the tale.