Inversion 3 Cell and Ideogram


chromosome 3 inversion metaphase cell


This metaphase cell is an example of a very subtle inversion. This is how the cell looks to a Cytogeneticist as it is viewed under a light microscope. In this case a segment in the q, or long arm of the indicated chromosome 3 is inverted. Since both breaks occurred in the long arm and the centromere is not involved, this is referred to as a paracentric inversion. The karyotype is written as: 46,XX,inv(3)(q24q27). The key to the karyotype description is as follows:
  • 46:  the total number of chromosomes.

  • XX:  the sex chromosomes (female).

  • inv(3):  inversion in chromosome 3.

  • (q24q27):  breakpoints of the inverted segment.


The following chromosome / ideogram comparison gives a detailed illustration of this inversion.

inversion 3 ideogram



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