Quantitative Model Provides Big Clues Into How Tiny Embryos Develop
A biological-mathematical-genetic model called TEMS, or Tissue Expansion-Modulated Maternal Morphogen Scaling, is providing insights into one of nature’s most intriguing genetic questions about scaling – the proportional growth of tissues, organs and structures from tiny ovaries, eggs and embryos.
The model provides new insights into the delicate connections between ovarian tissue and ensuing embryonic development, and it can be applied to future research into birth defects.
Developed by Biomedical Informatics Research scientist Jun Ma, PhD, and published March 26, 2015 in Nature Communications, the TEMS model was applied to fruit flies from development of the ovary through embryo. Ma’s team focused on two developmental components: morphogens – proteins that form concentration gradients along the axis of an embryo and instruct the genes that control the proportional formation of body parts and organs; and ovary-active genes that produce messengers delivered to the egg for instructing the production of morphogen proteins in the embryo.
His team studied front-to-back proportional scaling in embryos before organs start to develop and found that the size of embryos was influenced by the quantity of initial tissue in the female’s ovary, particularly the size of the ovarian egg chamber and the expansion of the copy numbers of an ovary-active gene called bicoid.
“The model provides a new perspective of embryonic development and contributes to our fundamental knowledge that may ultimately lead to an improved understanding of the basis of birth defects,” says Ma.
Of particular interest for future research, according to Ma, is the similarity between the peak number of bicoid gene copies in a female fly’s nurse cells and the peak number of cell nuclei in the offspring blastoderm, or early-stage embryo. Aided by TEMS, Ma and his team hope to better understand, quantify and predict how life forms grow and develop, and to explore the interplay between biology and evolution.
