How does our body know how to take shape from a single cell? Scientists are closing in on answers.

The coolest, most complicated machine is not an airplane, electric car or robot vacuum cleaner.

It’s you.

“You built yourself from a single cell, which no machine has ever had to do,” said Carole LaBonne, the president-elect for the Society for Developmental Biology and a professor at Northwestern University.

After fertilization, a cell goes on autopilot. It knows how to divide, multiply, differentiate — become a specific cell type — and organize itself into a complex, multicellular organism.

It’s the ultimate origin story.

So far, how this occurs, especially given the millions of ways embryonic development can go wrong, is still a mystery. But in an age of cutting-edge CRISPR gene editing; sophisticated microscopy; cheaper, faster DNA sequencing; advanced comparative genomics; and computational modeling; scientists are closing in on solving the puzzle.

In research institutes and university labs around the world, the excitement is palpable — if still off the public radar. But last month in Chicago, at the 82nd Annual Meeting of the society, 900 international researchers from all disciplines came together, and gave a sense of the urgency and anticipation surrounding their work.

They introduced breakthroughs in stem cell-derived human embryo-like models to better understand early embryonic development. They analyzed videos of fluorescent cells migrating in embryos, showing how far they have to travel. They compared CRISPR-generated mutants to human patients to better study diseases. And they presented new model organisms outside of the traditional lab rat.

The field of developmental biology has become “like a capstone project that encompasses cell and molecular biology, math, physics, genetics, chemistry,” said Jennifer Miskowski, a professor at the University of Wisconsin-La Crosse. We’re all “driven by questions about life.”

Development and disease go hand in hand

Early embryonic development is regulated by genes, proteins, and molecular pathways that must be turned on in the right place and at the right time. At any point, if something goes wrong, it can lead to birth defects.

According to the CDC, birth defects affect one in every 33 babies born in the United States each year. They are the leading cause of infant mortality. Congenital malformations include heart defects, craniofacial anomalies, like cleft lip/palate, and missing or abnormal limbs.

“Having a better understanding of when and how (development) goes wrong can help us think about best practices to help those families,” said Victoria Prince, former SDB president and a professor at the University of Chicago.

It can help researchers target genes that cause human disease, said Amber Carleton, a graduate student at the Medical College of Wisconsin investigating neurological disorders and brain formation.

After an embryo has formed, the genes and proteins involved turn off and usually stay off.

In some animals, normal cells do reactivate developmental genes during a process called regeneration.

Axolotls, zebrafish and hydra — freshwater polyps —can regrow entire body parts including their head, limbs, heart, brain and lungs after an injury.

Humans, on the other hand, cannot.

Studying how other organisms develop body parts and regenerate them could eventually lead to therapeutic applications in humans.

However, inappropriate activation can lead to cancer.

Cancer cells have learned to hijack developmental genes and reactivate ones that allow them to multiply rapidly, migrate long distances, and become multipotent, just like embryonic cells. This makes it easier for cancer cells to metastasize.

Researchers study a virtual zoo of animals

Due to ethical concerns, it’s almost impossible to study human development directly, though some scientists are now attempting to build human embryo-like models with stem cells.

Many researchers turn to animal models.

The Society for Developmental Biology conference featured a virtual zoo of animals — starfish, zebrafish, chicks, crustaceans, mice, nematodes, fruit flies, frogs, squid, cats and more.

Angel Banuelos, a graduate student who studies zebrafish craniofacial development at the University of Wisconsin-Madison, said the breadth of models “puts us into connection with other organisms.”

Each animal has its own set of advantages and limitations.

For example, zebrafish lay hundreds of tiny embryos at a time. The embryos/larvae are transparent during early development, so scientists can watch cells divide in real time and track them migrating throughout the animal’s body.

“Every time I look at them, I’m fascinated,” said Prince. “It’s really kind of a miraculous thing that we’re watching.”

Humans and zebrafish look nothing alike. But they share about 70% of the same DNA, making the animals useful proxies for understanding our own development.

Diversity is ‘rooted’ in development

Science doesn’t have to be centered around human health for it to matter. Developmental biologists also try to answer questions about the diversity of life.

How did giraffes develop long necks? Why do crustaceans have so many legs? What is the science behind the color of butterfly wings? How did squid and octopuses develop big brains? How did birds learn to sing?

Development is at the root of it all, said Prince.

But development is not fixed; biodiversity is threatened, for example, by climate change. The rapidly changing environment is forcing organisms to move or adapt.

LaBonne explained, “The more we understand about the basics of how embryos develop, the more we can understand how the changes that are happening in the environment are going to impact that going forward.”

If organisms can’t adapt and alter their development, they risk extinction that present risks to others in the ecosystem.

There’s a lot of interest about life all around us and all these different species, Prince noted. “Everything develops, but people don’t think about where they started.”