Complex sentence: Many Siamese cats from Thailand had a kink in their tails but over the years, this trait has been considered a flaw and breeders have largely eradicated it, although it persists among street cats in Thailand.
Split into simpler sentences: Many Siamese cats from Thailand had a kink in their tails, but over the years this trait has been considered a flaw. Breeders have largely eradicated it, but the kinked tail persists among street cats in Thailand.