Assoc. Prof. Dr. Ümit Özçelik, born in Aydın in 1978, graduated from the Ankara University Faculty of Medicine.

He completed his specialization training in General Surgery at Başkent University and has been actively working in the field of surgery for more than 20 years.

Throughout his career, he has participated in numerous organ transplantation surgeries, particularly kidney and liver transplantations, gaining extensive experience in this field.

He is also experienced in pediatric transplantation surgeries and advanced hepatobiliary surgery, taking an active role in surgical procedures involving pediatric patients.

Continuing his academic career as a faculty member at the Yeditepe University Faculty of Medicine, Dr. Özçelik also serves at the Yeditepe University Organ Transplantation Center.

Assoc. Prof. Dr. Ümit Özçelik has authored more than 30 national and international scientific publications, which have received over 400 citations.

Chimerism is the presence of cell groups with different genetic makeups within the same individual. Its inspiration comes from the mythological being Chimera—whose name in Greek means “female goat”—a composite creature formed from different animals.

Acquired chimerism may arise after organ and blood transplantation, stem cell therapies, or from unusual fusions during the fertilization process, and it can be temporary or permanent.

This phenomenon is regarded as one of the historical foundations of the idea of organ transplantation.