blas·​to·​cyst | \ ˈbla-stə-ˌsist How to pronounce blastocyst (audio) \

Definition of blastocyst

: the modified blastula of a placental mammal having an outer layer composed of the trophoblast

Examples of blastocyst in a Sentence

Recent Examples on the Web Science asked several researchers who have expertise in DNA sequencing about Rebrikov’s plan to search for off-target effects in blastocysts. Jon Cohen, Science | AAAS, "Embattled Russian scientist sharpens plans to create gene-edited babies," 21 Oct. 2019 But there could be other cells in the blastocyst that have unaltered GJB2 genes or off-target changes. Jon Cohen, Science | AAAS, "Embattled Russian scientist sharpens plans to create gene-edited babies," 21 Oct. 2019 But these extended pluripotent stem cells were able to form a structure similar to the blastocyst stage of an embryo, which the scientists called blastoids. San Diego Union-Tribune, "Artificial embryos draw closer with Salk Institute work in mice," 18 Oct. 2019 Now, researchers hope to also create blastocysts from the frozen northern white rhino sperm and the eggs collected from Najin and Fatu to create pure northern white rhino embryos. Jason Daley, Smithsonian, "Eggs Successfully Collected from the Last Two Northern White Rhinos," 24 Aug. 2019 Ultimately, four of these early embryos developed into blastocysts, or embryos that are beginning to differentiate. Rebecca Boyle, Discover Magazine, "The Quixotic Quest to Birth a Baby Northern White Rhino," 25 June 2019 Leaving embryos undisturbed from day one to day five —when the embryo becomes what’s known as a blastocyst—rather than checking on them on day three, as many centers do, has been similarly revolutionary. Jancee Dunn, Vogue, "How California Became the World’s Fertility Treatment Destination," 13 Mar. 2019 For now, these early embryos, called blastocysts, have been frozen. NBC News, "Scientists use test-tube science to save nearly extinct rhino," 4 July 2018 In mammals, a hollow sphere made out of fewer than 100 cells (called a blastocyst) forms days after an egg is fertilized. Laura Yan, Popular Mechanics, "This Artificial Embryo Actually Started Pregnancy In Mice," 5 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'blastocyst.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of blastocyst

1876, in the meaning defined above

History and Etymology for blastocyst

blasto- + -cyst

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Time Traveler for blastocyst

Time Traveler

The first known use of blastocyst was in 1876

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Cite this Entry

“Blastocyst.” Dictionary, Merriam-Webster, Accessed 21 Sep. 2020.

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More Definitions for blastocyst


blas·​to·​cyst | \ ˈblas-tə-ˌsist How to pronounce blastocyst (audio) \

Medical Definition of blastocyst

: the modified blastula of a placental mammal

More from Merriam-Webster on blastocyst Encyclopedia article about blastocyst

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