In mammals, identical twins arise when an embryo derived from a single fertilized egg splits into two independent embryos, producing two genetically identical individuals.

What limits might there be, from a developmental genetic viewpoint, as to when this can occur?

Key Concepts

Embryonic Development Stages

Embryonic development in mammals occurs in distinct stages, including cleavage, blastocyst formation, and gastrulation. The timing of these stages is critical, as the ability for an embryo to split into two independent embryos typically occurs during the early cleavage stage, before the cells begin to differentiate. Once differentiation begins, the potential for twinning decreases significantly.

Genetic Regulation of Development

Developmental genetics involves the study of how genes control the growth and differentiation of cells during embryonic development. Specific genes and signaling pathways regulate when and how cells divide and specialize. Disruptions or mutations in these genetic pathways can limit the embryo's ability to split and develop into two separate individuals.

Environmental Influences on Development

Environmental factors, such as maternal health, nutrition, and external stressors, can significantly impact embryonic development. These factors can influence gene expression and developmental timing, potentially affecting the embryo's ability to split. If the environment is not conducive to healthy development, it may limit the occurrence of identical twinning.