Editing Frog (section)

===Scientific research===
{{See also|Animal testing on frogs|Frogs in captivity}}
In November 1970, [[NASA]] sent two bullfrogs into space for six days during the [[Orbiting Frog Otolith]] mission to test weightlessness.

Frogs are used for [[dissection]]s in high school and university anatomy classes, often first being injected with coloured substances to enhance contrasts among the [[biological system]]s. This practice is declining due to [[animal welfare]] concerns, and "digital frogs" are now available for virtual dissection.<ref>{{cite news |title=California Schools Leading Race to Stop Dissections |url=http://awionline.org/content/california-schools-leading-race-stop-dissections |newspaper=Animal Welfare Institute |date=April 25, 2011 |access-date=June 17, 2012}}</ref>

Frogs have served as [[Animal testing|experimental animals]] throughout the history of science. Eighteenth-century biologist [[Luigi Galvani]] discovered the link between [[electricity]] and the [[nervous system]] by studying frogs. He created [[Frog galvanometer|one of the first tools]] for measuring [[electric current]] out of a frog leg.<ref>{{cite book |title=The science of common things: a familiar explanation of the first principles of physical science. For schools, families, and young students |last=Wells |first=David Ames |year=1859 |publisher=Ivison, Phinney, Blakeman |page=290 |url={{Google books|ajQAAAAAYAAJ|page=290|plainurl=yes}} }}</ref> In 1852, H. F. Stannius used a frog's heart in a procedure called a [[Stannius ligature]] to demonstrate the ventricle and atria beat independently of each other and at different rates.<ref>{{cite web |url=http://www.biology-online.org/dictionary/Stannius_ligature |title=Stannius ligature |date=October 3, 2005 |work=Biology online |access-date=August 5, 2012}}</ref> The [[African clawed frog]] or platanna (''Xenopus laevis'') was first widely used in laboratories in pregnancy tests in the first half of the 20th century. A sample of urine from a pregnant woman injected into a female frog induces it to lay [[egg]]s, a discovery made by English zoologist [[Lancelot Hogben]]. This is because a hormone, [[human chorionic gonadotropin]], is present in substantial quantities in the urine of women during pregnancy.<ref>{{cite journal | last1 = Sarkar | first1 = S. | title = Lancelot Hogben, 1895–1975 | journal = Genetics | volume = 142 | issue = 3 | pages = 655–660 | year = 1996 | doi = 10.1093/genetics/142.3.655 | pmid = 8849876 | pmc = 1207007}}</ref> In 1952, [[Robert William Briggs|Robert Briggs]] and [[Thomas J. King]] cloned a frog by [[somatic cell nuclear transfer]]. This same technique was later used to create [[Dolly (sheep)|Dolly the sheep]], and their experiment was the first time a successful nuclear transplantation had been accomplished in higher animals.<ref>{{cite web |url=http://www.pnas.org/site/misc/classics4.shtml |archive-url=https://web.archive.org/web/20121014105435/http://www.pnas.org/site/misc/classics4.shtml |archive-date=October 14, 2012 |title=Nuclear Transfer: Bringing in the Clones |author=Brownlee, Christen |work=Proceedings of the National Academy of Sciences of the United States of America |access-date=October 21, 2012}}</ref>

Frogs are used in cloning research and other branches of [[embryology]].  Although alternative pregnancy tests have been developed, biologists continue to use ''Xenopus'' as a [[model organism]] in [[developmental biology]] because their embryos are large and easy to manipulate, they are readily obtainable, and can easily be kept in the laboratory.<ref>{{cite web |url=http://people.ucalgary.ca/~browder/frogsrus.html |title=''Xenopus'' as a Model System in Developmental Biology |editor1=Browder, L.|editor2=Iten, L.|year=1998 |work=Dynamic Development |publisher=University of Calgary |access-date=June 17, 2012}}</ref> ''Xenopus laevis'' is increasingly being displaced by its smaller relative, ''[[Xenopus tropicalis]]'', which reaches its reproductive age in five months rather than the one to two years for ''X. laevis'',<ref>{{cite web | url=http://grants.nih.gov/grants/guide/rfa-files/RFA-HD-01-008.html | title=Developing the potential of ''Xenopus tropicalis'' as a genetic model |author=Klein, S.|publisher=Trans-NIH Xenopus Working Group |  access-date=March 9, 2006 }}</ref> thus facilitating faster studies across generations.

Genomes of ''Xenopus laevis'', ''X. tropicalis'', ''Rana catesbeiana'', ''Rhinella marina'', and ''Nanorana parkeri'' have been sequenced and deposited in the [[National Center for Biotechnology Information|NCBI]] Genome database.<ref>{{Cite web|url=https://www.ncbi.nlm.nih.gov/genome/browse/#!/overview/Amphibia|title=Genome List – Genome |website=NCBI |access-date=April 7, 2019 |url-status=dead |archive-url=https://web.archive.org/web/20190713120919/https://www.ncbi.nlm.nih.gov/genome/browse/#!/overview/Amphibia |archive-date= July 13, 2019 }}</ref>