Pericentric chromosome inversion:
deletion meiotic products
The locus order in the bottom chromosome is inverted with respect to B & C: the inversion includes
the centromere, and is therefore called a pericentric inversion.
During meiosis, pairing of the inverted region requires that the
inverted chromosome form a loop with respect to the standard
chromosome. This produces duplication
and deletion products, that is, chromatids that have extra loci
as well as missing some.
To prove this, start at the centromere in the
topmost pair of chromatids, and trace the chromatids attached to this
centromere in both directions. Note that the top chromatid has the
standard arrangement of loci (ABoCD),
but the second chromatid is ABoCA,
that it has a duplicate A
locus and lacks the D locus.
Satisfy yourself that the third chromatid is DBoCD,
that is, missing an A and with
an extra D, the exact
complement of the other duplication/deletion product.
by Griffiths et al.; all text
©2010 by Steven M. Carr