Gene knockout makes female mice masculine

The mammalian fucose mutarotase enzyme is known to be involved in incorporating the sugar fucose into protein. Female mice that lack the fucose mutarotase (FucM) gene refuse to let males mount them, and will attempt copulation with other female mice. Researchers writing in BioMed Central’s open access journal BMC Genetics created the FucM mouse mutants in order to investigate the role of this enzyme in vivo.

Chankyu Park worked with a team of researchers from the Korea Advanced Institute of Science and Technology and intriguingly gained some insight into the neurological basis of sexual preference. He said, “The FucM knockout mice displayed drastically reduced sexual receptivity, although pregnancy after forced mating attempts by normal sexually experienced males showed that the animals were fertile. The FucM knock-out mice have reduced levels of alpha-fetoprotein, a protein thought to be involved in development of parts of the brain responsible for reproductive behavior”.

The mutant female mice were healthy, and behaved normally towards young mice. When approached by male mice, however, they would not adopt the sexually receptive ‘lordosis’ position. Furthermore, they lost interest in investigating male urine, unlike normal females, and would attempt to mount other females. Speaking about the results, Park said, “We speculate that these behavioural changes are likely to be related to a neurodevelopmental change in pre-optic area of the female mutant brain , becoming similar to that of a normal male”.

Notes to Editors

1. Male-like sexual behavior of female mouse lacking fucose mutarotase

Dongkyu Park, Dongwook Choi, Junghoon Lee, Dae-sik Lim and Chankyu Park

BMC Genetics 2010, 11:62 doi:10.1186/1471-2156-11-62

Article available at the journal website:

Please name the journal in any story you write. If you are writing for the web, please link to the article. All articles are available free of charge, according to BioMed Central’s open access policy.

2. ‘FucM’ is the legitimate abbreviation for fucose mutarotase assigned by the researchers.

3. BMC Genetics is an open access journal publishing original peer-reviewed research articles in all aspects of inheritance and variation in individuals and among populations. BMC Genetics (ISSN 1471-2156) is indexed/tracked/covered by PubMed, MEDLINE, BIOSIS, CAS, EMBASE, Scopus, Zoological Record, CABI, Thomson Reuters (ISI) and Google Scholar.

4. BioMed Central ( is an STM (Science, Technology and Medicine) publisher which has pioneered the open access publishing model. All peer-reviewed research articles published by BioMed Central are made immediately and freely accessible online, and are licensed to allow redistribution and reuse. BioMed Central is part of Springer Science+Business Media, a leading global publisher in the STM sector.

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