A transgenic mouse that has the one specific desired gene disrupted is called
knock out mice
Transgenic animals are animals (most commonly mice) that have had a foreign gene deliberately inserted into their genome.
A knockout mouse or knock-out mouse is a genetically modified mouse (Mus musculus) in which researchers have inactivated, or "knocked out", an existing gene by replacing it or disrupting it with an artificial piece of DNA.
A clone of a mouse is a mouse that is genetically identical to an original mouse.
A chimeric mouse is one that has cells which are genetically different or distinct from each other.