Novel Japanese model sheds light on embryo development

To understand how life began, researchers from Kyoto University have created a lab-based human germ cell development model that reveals how "germ cells" pass genetic traits from one generation to the next.

Though in early stages, the team's model is hoped to form a foundation for continuing studies on germ cell lineage.

"By further reconstituting human germ cell development in vitro, we may be able to discover the mechanisms throughout the entire developmental process from embryo to adult," said lead researcher professor Mitinori Saitou.

The underlying mechanisms of early germ cell development in humans have remained unclear because of a lack of robust experimental methods as well as inherent difficulties with studying human embryos.

In a promising breakthrough, published in the journal Cell Stem Cell, the research team recreated human germ cell development in the laboratory, revealing specific key elements and events that occur at the beginning of human life.

To date, most such research has been restricted to mice.

While this work provides useful information that is generally applicable to mammals, there has still been a lack of information specific to humans.

To that end, the team recreated the developmental process of human germ cells which gives rise to reproductive sperm and eggs.

The scientists gained insight into how epigenetic marks -- traits that are inherited without changes to the DNA sequence -- are "erased" at the beginning of germ cell development.

"We demonstrated the early events in human germ cell development. Our work should provide a basis to gain a better understanding of how certain disorders such as infertility and growth impairment come about," Sasaki explained.