The First and Current Checklist of the Animal Species Bearing Lampbrush Chromosomes

In virtually all animal species, egg cells exhibit a notable size disparity compared to somatic cells in order to support the production of an embryo. The rapid and voluminous production of eggs, often in abundance, necessitates specialized mechanisms. Among these mechanisms is diplotene arrest, a stage characterized by nuclear expansion and heightened chromosomal transcriptional activity, resulting in the formation of distinct lampbrush chromosomes. Remarkably long chromosomes, lampbrush chromosomes have been best studied in amphibians and birds due to their ease of isolation from the nucleus. A thorough review of scientific literature conducted until March 2025 across electronic databases unveiled the presence of lampbrush chromosomes in a total of 197 animal species, encompassing 31 invertebrates and 166 vertebrates. The widespread occurrence of lampbrush chromosomes across such a diverse array of animal species suggests an ancient evolutionary origin for this mechanism of egg growth.