Human-pig 'chimera embryos' detailed

By James Gallagher Health and science reporter, BBC News website


26 January 2017

Embryos that are less than 0.001% human - and the rest pig - have been made and analysed by scientists.

It is the first proof chimeras - named after the mythical lion-goat-serpent monster - can be made by combining material from humans and animals.

However, the scientific report in the journal Cell shows the process is challenging and the aim of growing human organs in animals is distant.

It was described as an "exciting publication" by other researchers.

To create a chimera, human stem cells - the type that can develop into any tissue - are injected into a pig embryo. Image copyright Juan Carlos Izpisua Belmonte Image caption The spherical pig embryo is held in place while a tiny needle is used to inject human cells

The embryo - now a mix of human and pig - is then implanted into a sow for up to one month.

The process appears very inefficient - of the 2,075 embryos implanted only 186 continued to develop up to the 28-day stage.

But crucially there were signs that human cells were functioning - albeit as a tiny fraction of the total tissue - as part of a human-pig chimera.

"This is the first time that human cells are seen growing inside a large animal," Prof Juan Carlos Izpisua Belmonte, from the Salk Institute, told the BBC News website.

Continued 

Rare Fossilized Embryos More Than 500 Million Years Old Discovered By Researchers

April 11, 2014

Jeff Sossamon, University of Missouri

The Cambrian Period is a time when most phyla of marine invertebrates first appeared in the fossil record. Also dubbed the “Cambrian explosion,” fossilized records from this time provide glimpses into evolutionary biology when the world’s ecosystems rapidly changed and diversified. Most fossils show the organisms’ skeletal structure, which may or may not give researchers accurate pictures of these prehistoric organisms. Now, researchers at the University of Missouri have found rare, fossilized embryos they believe were undiscovered previously. Their methods of study may help with future interpretation of evolutionary history.

“Before the Ediacaran and Cambrian Periods, organisms were unicellular and simple,” said James Schiffbauer, assistant professor of geological sciences in the MU College of Arts and Science. “The Cambrian Period, which occurred between 540 million and 485 million years ago, ushered in the advent of shells. Over time, shells and exoskeletons can be fossilized, giving scientists clues into how organisms existed millions of years ago. This adaptation provided protection and structural integrity for organisms. My work focuses on those harder-to-find, soft-tissue organisms that weren’t preserved quite as easily and aren’t quite as plentiful.”

Read more at

For the First Time Iberian Lynx Embryos Are Collected and Preserved

Mar. 22, 2013 — A pioneering procedure in felines allows the collection of biological material from Iberian lynx females before castration. The preserved biological material of the lynxes will be used in future conservation breeding programmes.

In February two Iberian lynx females who belong to the Iberian lynx Conservation Breeding Program (ILCBPS) were castrated in order to guarantee a better quality of life and prevent possible health problems.

Scientist from the Leibniz Institute for Zoo and Wildlife Research IZW, Berlin, Germany, went to the breeding centers in Spain and Portugal to obtain embryos by flushing the oviducts and freeze ovarian tissue immediately after surgery. The obtained embryos and ovarian pieces are stored in liquid nitrogen. Now they are kept at the Museo Nacional de Ciencias Naturales de Madrid (CSIC) for further usage in the breeding programme.

The specialists of the IZW performed a pioneering procedure to obtain and freeze embryos in a wildlife species. Based on their experience in the domestic cat, they developed a method for cryopreserving oocytes and embryos of wild cat species. "Seven days after mating we expected to flush embryos from the uterus. In both cases, however, oocytes and embryos were still within the oviducts. Thus, the embryo development in lynxes is slower than in domestic cats," says Prof Katarina Jewgenow from the IZW specialist team.

Continued:  http://www.sciencedaily.com/releases/2013/03/130322090751.htm

Earliest Pregnant Reptile Pushes Back Fossil Record of Live Birth

Charles Choi, LiveScience Contributor 

Newly found fossils of embryos from the first aquatic reptiles called mesosaurs — along with a pregnant female — may be the oldest known example of birth given to live young instead of eggs, scientists report.

Both mammals and reptiles wrap their developing embryos in protective layers, something that helped the little ones survive and ultimately helped their ancestors conquer the land. Mammals often keep these membrane-swaddled offspring within them, giving birth to live young, while reptiles typically lay their membrane-bundled progeny in eggs.

However, there are some oddballs: Some mammals, such as the platypus, lay eggs, while some reptiles, such as most vipers, are viviparous, giving birth to live young.

The fact that mammals and reptiles surround their embryos with these protective layers makes them  known as amniotes. The fossil record of amniotic eggs and embryos is very sparse, and as such, scientists have little information about when, how and why they evolved.

Read on:  http://www.livescience.com/19044-earliest-pregnant-reptile-live-birth.html