Genes in the NK4 Class Are Involved in Heart Development

Multiple Choice

Genes in the NK4 class are involved in heart development in both vertebrates and fruit flies.They are also involved in the development of pumping organs in organisms that lack a heart,such as roundworms and cnidarians.Available information suggests that in early animals,the ancestral NK4 gene and its associated regulatory network ________.

A) evolved convergently in vertebrates and arthropods
B) were important in the development of the heart and blood vessels
C) evolved by duplication of the Hox cluster
D) governed the development of some fluid-filled pumping structure
E) did not have any function