Yoga Sutras of Patanjali · 4.2

जात्यन्तरपरिणामः प्रकृत्यापूरात्॥२॥

jātyantarapariṇāmaḥ prakṛtyāpūrāt

Transformation from one species or birth-class into another comes about through the in-flowing of nature itself.

— Yoga Sutras of Patanjali 4.2

Source: Sanskrit attributed to Patanjali (c. 2nd century BCE – 4th century CE). Public-domain English readings drawn from Swami Vivekananda's 'Raja Yoga' (1896) and Charles Johnston's 'The Yoga Sutras of Patanjali' (1912).