The evolution of multicellularity in animals has primarily occurred by the
A) remodeling of old genes.
B) deletion of many old genes.
C) production of many new genes.
D) deletion of many old chromosomes.
E) fusion of genes from many ancestral organisms.

Question

Quizplus · Accepted Answer

The remodeling of old genes has played a major role in the evolution of multicellularity in animals. This involves changes in the regulation of existing genes, duplication of genes, and alterations in protein function. This process has allowed for the development of specialized cells and tissues, which is a key characteristic of multicellular organisms. Deletion of old genes or chromosomes may occur, but it is not the primary mechanism for the evolution of multicellularity in animals. The production of many new genes is also not the primary mechanism, as the majority of genes involved in multicellularity likely existed in ancestral single-celled organisms. Fusion of genes from many ancestral organisms is also not necessary, as the genes required for multicellularity likely existed in a common ancestor of all animals.

The Evolution of Multicellularity in Animals Has Primarily Occurred by the