American embryo breeds hybrid half-human half-chicken

The US team of researchers embodies embryonic stem cells and chicken embryos in an attempt to cure developmental disorders.

Scientists headed by Ali Brivanlou at Rockerfeller University in New York combine chicken embryonic stem cells in a study published May 23 in the journal Nature, according to Live Science. Their goal is to look at how embryonic cells arrange themselves, in order to better understand the process of embryonic development and how cells make specialized body structures.

Combining human stem cells with animal embryos produces a hybrid species (chimera).

The developing embryonic cell transplantation experiment has been around for 100 years. In 1924, this type of experiment in amphibians helped researchers to discover 'organized regions' , embryonic cells that control the development of other cells. But the region of primate embryonic primate cells (including humans) has not been determined. The new study describes the first evidence of human organism, marking an important breakthrough in understanding developmental biology.

Due to the moral limitations of studying human embryos, experiments that examine human organism are only carried out with stem cells, then grafted onto other animal embryos such as chickens. Combining human stem cells with animal embryos produces specimens, containing cells from both host and cell donors. Therefore, these hybrid species have two DNA sequences.

Since 2016, scientists have incorporated pig and sheep embryonic stem cells to study the ability to develop human organs in animals. In 2017, experiments to produce the world's first surviving pig embryo can contain human cells.

Human stem cells (red) when implanted into chicken embryos.(Graphic: Rockerfeller University).

In the new study, the authors used a special type of disc to grow early human stem cells and add growth-promoting proteins. They found that after injecting more proteins called Wnt and Activin , stem cells began to form tissue. This is the tissue that produces proteins that is commonly found in the organized area.

But the real challenge lies in what happens after the team joins this cell cluster with the developing embryo. When they introduced clusters of stem cells into chicken embryos, human cells persisted and mixed with host cells. Human cells form a type of tissue that helps form the spine and the cells also begin to instruct the chicken embryonic cells to transform the tissue into the nervous system.