Primordial Germ Cells were Created from Human Stem Cells to Potentially Crack the Genetic Inheritance Code
The recent discovery of a newfound role of a gene called SOX17 led scientists from University of Cambridge and Weizmann Institute to create primordial germ cells (PGCs)—egg and sperm predecessors—from human stem cells. Previously, PGCs were created using rat and mice stem cells, and a few scientists have created germ cells from human stem cells, but this is the first time where primordial germ cells were refashioned from human stem cells efficiently. With this new tool in their arsenal, the researchers are hoping to shed light on the mechanisms that regulate transmission of genetic material from one generation to the next.
During the early stages of embryo development, after an egg cell is fertilized by a sperm cell, the new entity (called a zygote) undergoes a series of cell division until it forms a bundle of cells known as a blastocyst. It consists of an inner cell mass, which develops further until it eventually forms the fetus, and an outer wall that later forms the placenta. Cells in the inner cell mass are rebooted to become stem cells, in which a handful are “specified” into becoming primordial germ cells, which then become germ cells (sperm or egg). Sperm and egg cells are responsible for handling the genetic information that is to be passed down to the next generation.
Scientists knew SOX17 played a role in directing stem cells to become endodermal cells which later form the gut, pancreas, and lungs. Further study led the researchers to discover SOX17’s role in PGC specification from human stem cells and also ascertained that primordial germ cells can be made from reprogrammed adult skin cells, opening doors to new insights on infertility issues and germline tumors, and possibly epigenetic inheritance process.
It’s been known the environment, such as smoking and dietary habits, can impact our genes by methylating, or adding chemical particles, to DNA, which act as dimmer switches that increase or decrease the activity of genes. Methylation patterns can be passed down to offsprings. The researchers conveyed during PGC specification, a de-methylation program commences and virtually resets the primordial germ cells. Nevertheless, traces of these patterns might still be inherited, in which why they occur remain a mystery. Unlocking the reason behind epigenetic inheritance can give scientists clues to comprehending age-related diseases and uncover the secret to eternal youth.