Centrioles are subcellular organelles found at the cilia base with an evolutionarily conserved structure and a shock absorber-like function. In sperm, centrioles are found at the flagellum base and are essential for embryo development in basal animals. Yet, sperm centrioles have evolved diverse forms, sometimes acting like a transmission system, as in cattle, and sometimes becoming dispensable, as in house mice. How the essential sperm centriole evolved to become dispensable in some organisms is unclear. Here, we test the hypothesis that this transition occurred through a cascade of evolutionary changes to the proteins, structure, and function of sperm centrioles and was possibly driven by sperm competition. We found that the final steps in this cascade are associated with a change in the primary structure of the centriolar inner scaffold protein FAM161A in rodents. This information provides the first insight into the molecular mechanisms and adaptive evolution underlying a major evolutionary transition within the internal structure of the mammalian sperm neck.

Background/Objectives: Modern breast reconstruction has undergone substantial evolution, with implant-based, pedicled autologous, and free autologous techniques. The purpose of this study is to review the current state of the art in free autologous breast reconstruction, highlighting advancements in the types of flaps, donor site selection, techniques, and functional restoration. Methods: A literature review was conducted using PubMed to capture studies related to well-known free flaps that are used for breast reconstruction. Studies for each flap type were reviewed and sorted for inclusion into one of six categories: (1) clinical outcomes, (2) comparison studies of alternative flaps, (3) preoperative planning, (4) flap classifications and perfusion zones, (5) technique descriptions, and (6) time and cost analyses. Results: The majority (77%) of articles included were written on various types of abdominally based free flaps, including TRAM, DIEP, and SIEA flaps. These studies indicated an evolution in technique over time to minimize donor site morbidity, improve patient-reported and functional outcomes, improve efficiency, and expand clinical indications. The remaining 23% of articles discussed alternative flap choices, including PAP, TUG, S/IGAP, and LAP flaps. Studies highlighted technical challenges and the evolution of techniques to make these flaps more accessible, as well as how to combine flaps to expand clinical indications. Conclusions: Autologous breast reconstruction has evolved significantly, with advancements in techniques such as robotic-assisted surgery, multi-flap reconstruction, bipedicled flaps, and neurotization. This review highlights the current best practices while acknowledging ongoing challenges and the potential for future innovations in microsurgery, nerve regeneration, and personalized medicine, which hold promise for further refining outcomes.

Centrioles are subcellular organelles found at the cilia base with an evolutionarily conserved structure and a shock absorber-like function. In sperm, centrioles are found at the flagellum base and are essential for embryo development in basal animals. Yet, sperm centrioles have evolved diverse forms, sometimes acting like a transmission system, as in cattle, and sometimes becoming dispensable, as in house mice. How the essential sperm centriole evolved to become dispensable in some organisms is unclear. Here, we test the hypothesis that this transition occurred through a cascade of evolutionary changes to the proteins, structure, and function of sperm centrioles and was possibly driven by sperm competition. We found that the final steps in this cascade are associated with a change in the primary structure of the centriolar luminal protein FAM161A in rodents. This information provides the first insight into the molecular mechanisms and adaptive evolution underlying a major evolutionary transition within the internal structure of the mammalian sperm neck. Graphical Highlights: – Barrel-shaped centrioles are present in all rodents except members of the Muridae taxonomical family. – The FAM161A sequence evolved selectively in rodents and specifically in a murid subgroup. – The evolution of centriole degradation is correlated with the expression of a novel FAM161A isoform. – The ancestral centriole remodeling program involves elongation followed by redistribution. – The mouse centriole degradation program involves elongation followed by elimination.