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Updated: Aug 13, 2026

Germ Cell Transplantation and Testis Tissue Xenografting in Mice
Published on: February 6, 2012
The testis-specific apoptosis related gene TTL.6 underwent adaptive evolution in the lineage leading to humans
Xiao-hua Chen1, Hong Shi, Xiao-Lin Liu
1Key Laboratory of Cellular and Molecular Evolution, Kunming Institute of Zoology, The Chinese Academy of Sciences (CAS), Kunming, China.
Abstract:
The TTL.6 gene is a member of the tubulin-tyrosine ligase (TTL) family involved in apoptosis and preferentially expressed in the testis. We sequenced the coding region and part of the introns of TTL.6 in world wide human populations and five representative nonhuman primate species covering great apes, lesser ape and Old World monkey. The sequence substitution patterns of TTL.6 in primates demonstrated a sharp difference in evolutionary rates among different primate lineages. Our results indicated an accelerated evolution of TTL.6 in the human lineage, which was caused by Darwinian positive selection. Further analysis on sequence variations in human populations demonstrated an excess of derived common alleles, which was likely caused by genetic hitchhiking, an implication of recent positive selection on TTL.6 in human populations.
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