Secrets of life in a spoonful of blood

Abstract

L ife starts with a puzzle. Out of sight in a mother's womb, 3 billion letters of DNA code somehow turn into 3D bodies, all in the space of a mere 40 weeks. Fetuses form eyes, brains, hearts, fingers and toes -in processes that are meticulously coordinated in both time and space. Biologists have pieced together parts of this puzzle, but many gaps remain. Now, a crop of molecular technologies is giving scientists tantalizing hints about how to fill in those gaps. Improved ways of reading and interpreting the information in fetal genetic material are uncovering a raft of genes involved in human development, and letting researchers eavesdrop on the hum of gene activity before birth. They can see which genes turn on or off at pivotal moments, and sense how the environment nurtures or intrudes on this.Even the vital life-support system that we jettison at birth -the Womb with a viewThe intricate development of the fetus is yielding its long-held secrets to stateof-the-art molecular technologies. © 2 0 1 7 M a c m i l l a n P u b l i s h e r s L i m i t e d , p a r t o f S p r i n g e r N a t u r e . A l l r i g h t s r e s e r v e d . BY C L A I R E A I N S W O R T HILLUSTRATIONplacenta -is laying bare its secrets. "It really is this great mystery in reproduction, " says Zev Williams, a reproductive endocrinologist and infertility specialist at the Albert Einstein College of Medicine in New York City. "It's obviously such a critical part of human development, but it's been so understudied. " Until now, much of the work has relied on amniotic or placental samples obtained during routine invasive tests such as amniocentesis. But scientists are eyeing the next step: studies that are non-invasive for the fetus and are done on a teaspoonful of blood drawn from a pregnant woman's arm. In this way, researchers could monitor fetuses as they develop and, down the line, develop non-invasive tests for a broad range of conditions, in both fetus and mother.Physicians are already moving towards treating fetuses in the womb on the basis of such diagnoses. "It's an exciting time, " says Mark Kilby, a fetal-medicine specialist at the University of Birmingham, UK.But it won't be plain sailing. The technologies are developing so quickly that scientists are struggling to interpret the information they yield and are facing knotty ethical quandaries. What, for example, should doctors do if non-invasive prenatal testing (NIPT) reveals a DNA sequence that sometimes causes disease -but not always? "That is what we have to discuss as a whole community, " says clinician and geneticist Dennis Lo of the Chinese University of Hong Kong, who was the first to find fetal DNA in a mother's blood 1 . DEVELOPMENT WORKProbing fetal development starts, naturally enough, with DNA, the recipe for life. Developmental biologists have already gathered a trove of information here, through studies of laboratory animals from worms to mice, identifying many genes and processes that have human equivalents. Painstaking detective work on families with inherited gene...

The genome, microbiome and evolutionary medicine

“…Modern obstetrical care screens for these diseases, and genomics now enables detection of fetal DNA in maternal blood and offers the prospect for improved control. 48,49…”