A system was developed to track adipogenesis in white adipose tissue (WAT) using the AdipoChaser mouse, which allows for inducible, permanent labeling of mature adipocytes. This system was used to study adipogenesis during development, high-fat diet (HFD) feeding, and cold exposure. The study revealed that during cold-induced 'browning' of subcutaneous fat, most 'beige' adipocytes stem from de novo-differentiated adipocytes. During HFD feeding, epididymal fat initiates adipogenesis after 4 weeks, whereas subcutaneous fat undergoes hypertrophy for up to 12 weeks. Gonadal fat develops postnatally, while subcutaneous fat develops between embryonic days 14 and 18. The results highlight the extensive differences in adipogenic potential among various fat depots. The study also found that cold exposure or β3 agonist treatment in subcutaneous adipose tissue induces massive white adipogenesis in epididymal adipose tissue, suggesting that these beige adipocytes arise from de novo differentiation rather than transdifferentiation of existing white adipocytes. Additionally, subcutaneous adipose tissue shows minimal de novo adipogenesis in response to chronic caloric excess, unlike epididymal adipose tissue, which undergoes significant adipogenesis after prolonged HFD exposure. During development, subcutaneous adipocytes show adipocyte commitment and differentiation starting around embryonic days 14-18, while gonadal adipocytes differentiate postnatally. The study also demonstrated that cold exposure or β3 agonist treatment induces widespread white adipocyte differentiation in epididymal adipose tissue, a phenomenon distinct from the browning effect seen in subcutaneous adipose tissue. These findings highlight the unique characteristics of different fat depots and their responses to various physiological challenges. The AdipoChaser mouse provides a valuable tool for studying adipocyte dynamics in different fat depots, offering insights into the mechanisms underlying adipose tissue expansion and regeneration.A system was developed to track adipogenesis in white adipose tissue (WAT) using the AdipoChaser mouse, which allows for inducible, permanent labeling of mature adipocytes. This system was used to study adipogenesis during development, high-fat diet (HFD) feeding, and cold exposure. The study revealed that during cold-induced 'browning' of subcutaneous fat, most 'beige' adipocytes stem from de novo-differentiated adipocytes. During HFD feeding, epididymal fat initiates adipogenesis after 4 weeks, whereas subcutaneous fat undergoes hypertrophy for up to 12 weeks. Gonadal fat develops postnatally, while subcutaneous fat develops between embryonic days 14 and 18. The results highlight the extensive differences in adipogenic potential among various fat depots. The study also found that cold exposure or β3 agonist treatment in subcutaneous adipose tissue induces massive white adipogenesis in epididymal adipose tissue, suggesting that these beige adipocytes arise from de novo differentiation rather than transdifferentiation of existing white adipocytes. Additionally, subcutaneous adipose tissue shows minimal de novo adipogenesis in response to chronic caloric excess, unlike epididymal adipose tissue, which undergoes significant adipogenesis after prolonged HFD exposure. During development, subcutaneous adipocytes show adipocyte commitment and differentiation starting around embryonic days 14-18, while gonadal adipocytes differentiate postnatally. The study also demonstrated that cold exposure or β3 agonist treatment induces widespread white adipocyte differentiation in epididymal adipose tissue, a phenomenon distinct from the browning effect seen in subcutaneous adipose tissue. These findings highlight the unique characteristics of different fat depots and their responses to various physiological challenges. The AdipoChaser mouse provides a valuable tool for studying adipocyte dynamics in different fat depots, offering insights into the mechanisms underlying adipose tissue expansion and regeneration.