The success of the embryonic stem (ES) cells from cattle.

After decades of effort, scientists eventually succeeded in obtaining stem embryonic (ES) cells from cattle and keeping them in their original state in a petri dish.
acquire these versatile cells that can be turned into tissues ranging from skin to muscles and bones will make it easier to adjust and preserve the genetic traits of beef and dairy breeds.
this, in turn, has led to animals that produce more milk or tender beef, who face fewer complications when producing cubs, and who are more resistant to disease.
the discovery may also open the way for studying the basic development of cattle and becoming a model of human disease.
"I thought I wouldn't have seen this happen in my life."
," said Jose Cibelli, a developmental biologist at Michigan State University.
he was one of the team members who tried to acquire bovine ES cells in the late 1990s.
in many efforts since then, when stem cells from cow embryos are grown in the lab, they develop into other cell types.
means they quickly lose their dispotle.
1981, scientists successfully isolated mouse ES cells, allowing them to study early embryonic development and test the effects of genetic defects. Shortly after
, the researchers turned their attention to cattle.
, however, it wasn't until 1998 that researchers found the right nutrient medium to grow human ES cells.
as one of the team members currently isolating cattle ES cells, Jun Wu has paid little attention to cattle throughout his career.
stem cell biologist from Southwest Medical Center in Texas has been more interested in getting new stem cell types from mice and humans.
he is also interested in developing chimerics that mix cells from two species, such as pigs that have human cells and may one day grow transplanted organs.
2015, he and his co-authors reported finding the right culture conditions for new human pluripotent stem cells that could easily grow in laboratories and mice.
, however, one of the project's collaborators targeted another study.
, A.
, a reproductive biologist at the University of California, Davis, who previously worked at Cibelli's lab, hopes that these same conditions may eventually sustain the growth of ES cells from livestock.
this makes it easier to improve the genetic traits of animals.
, the team, which also includes developmental biologist Juan Carlos Izpisa Belmonte and his team at the Salk Institute in San Diego, exposed stem cells isolated from cattle embryos to new media.
the mixture has two key components: the protein that causes cells to grow and multiply, and another molecule that inhibits them to differentiate into more mature cell types. "They used both the 'accelerator' and the 'brake pads', "
.
" rancher, said George Seidel, a reproductive physiologist at Colorado State University.
result: After more than a year of growth in the lab, the cells remain multi-energy.
"Many of my colleagues and students have been trying to do this for years.
," Seidel said.
when injected into mice with a weakimmune system, these cells grow into monoliths abody of multiple cells -- a key feature of truly pluripotent stem cells.
researchers report the results in the Proceedings of the National Academy of Sciences.
, however, Seidel says interest in bovine ES cells has waned with the development of cloning technology.
using the same technique used to produce Dolly sheep, where DNA from adult cells is implanted into eggs that remove DNA, livestock breeders can replicate the genetic traits of the animals they want, such as fast growth or abundant milk production.
the breeds of bulls that own these traits are lucrative for breeders because they can sell sperm to beef and milk producers, who use it to artificially insemination cows and bring better traits to the next generation.
, however, Cibelli says, the cells that are commonly used to produce these clones - connective tissue cells called fibroblasts -- are short-lived and can only divide 20 or 30 times.
with ES cells that can survive for a long time, breeders can more easily capture the dominant cell line and edit the cattle genome in multiple rounds using techniques such as CRISPR.
Even without genetic modification - a technique that consumers may not want to see for steaks and milkshakes - ES cells can make it easier for breeders to choose the dominant animal.
they can test ES cells from different embryos to look for genetic advantages such as genes associated with more milk production.
Cibelli says that once the desired series of traits is identified, researchers can use these cells to create infinite clones.
the most exciting application for Ross depends on his team's current work to illustrate how these ES cells can develop into sperm and egg cells in cattle.
If they succeed, Livestock Genetics could combine these sperm and eggs to create embryos with new genetic combinations and then isolate more stem cells from the best embryos.
they can use this cycle - stem cells, sperm and egg cells, embryos, stem cells - to accelerate the improvement of the traits of offspring without the need for any animals to be born.
this means that the time it takes for cattle to become pregnant is shorter and fewer animals are wasted.
" it accelerates the genetic progress by several orders of magnitude.
," Ross said.
.