Genome complexity in embryology (Introduction)

by David Turell , Friday, April 24, 2015, 18:05 (3502 days ago) @ David Turell

A new discovery is that the organelle, the centriole, which organizes mitosis, comes from sperm in the zygote, and seems to drive embryogenesis for up to 10 generations of cells and therefore is suspected of carrying information for the whole process of development. This is outside the genome:-http://www.sciencedaily.com/releases/2015/04/150424085630.htm-"Perhaps best known for their role in cell division, centrioles ensure that chromosomes are properly passed on to the new daughter cells. However, they are also found in cilia, the long eyelash-like structures that allow many cells in the body to signal to their neighbors and other cells to exhibit motility, e.g. in cells that line the respiratory tracts. During reproduction, both parents equally contribute genetic material, while the female egg donates most of the cell organelles, such as mitochondria. However, the centrioles of the newly fertilized embryo come exclusively from the male's sperm, bringing with them any malfunctions to the first embryo cells.-"The lab of Pierre Gönczy at EPFL's Swiss Institute for Experimental Cancer Research has found that centrioles can carry such information beyond the first cells to many of a developing embryo to several cell generations. The study focused on the worm C. elegans, which is commonly used as a model organism for embryonic development and human genetic diseases. As in other species, including humans, centrioles in C. elegans are only contributed by sperm cells. Gönczy's team wanted to know how far do these "original" centrioles last across the cell divisions that turn a fertilized egg into a fully formed embryo.-"Gönczy's team imaged the fluorescent signals at different cell divisions of the developing embryos, and discovered that paternally contributed centriole proteins can actually persist up to ten cell generations. The data show for the first time that centrioles are remarkably persistent in the developing embryo.-"Even more intriguing are the implications the study has for biology at large, as it raises the possibility that centrioles, persisting across several cell cycles, could effectively be a non-genetic information carrier. If this were confirmed, it could represent a paradigm shift in the way we think and understand the biology of an organelle that has been present across eukaryotic evolution."-Complexer and complexer