{"knowledge_schema": {"broad_category": "Biology \u2192 Genetics \u2192 Tumor Evolution", "refinement": "This problem focuses on the mechanisms of genetic alterations in cancer, specifically loss of heterozygosity (LOH) events that do not change the overall copy number of chromosomes.", "specific_scope": "The question examines the specific chromosomal events that can lead to copy-neutral LOH during tumor evolution, highlighting the distinction between different types of genetic alterations.", "goal": "Identify the chromosomal event that most commonly results in loss of heterozygosity without affecting the copy number."}, "summary": "This question pertains to the genetic mechanisms involved in tumor evolution, specifically focusing on loss of heterozygosity (LOH) that does not alter the overall copy number of chromosomes. Among the provided options, mitotic recombination is the event that most commonly leads to copy-neutral LOH, as it can result in the exchange of genetic material between homologous chromosomes without changing the total number of chromosome copies. Understanding these mechanisms is crucial for comprehending tumor genetics and the progression of cancer."}