Nontraditional Inheritance

[Keith Robison]

Belinda J.F. Rossiter (rossiter at bcm.tmc.edu) wrote:
: In article <36q2ak$k7r at vixen.cso.uiuc.edu>, dstone at prairienet.org (David
: M. Stone) wrote:

: >         I recently received a grant for a teacher update workshop.
: > I am interested in having a number of speakers present regarding 
: > a number of topics. Can anyone tell me specifically which topics
: > fit under the "umbrella" of nontraditional inheritance?

The already mentioned trinucleotide repeat expansion concept is a good
one.  It is nontraditional because the severity of the disease can increase
with each transmission of the disease allele.  This is due to the
expansion of the unstable repeat (there is a pre-explanation term
for this phenomenon which escapes me).

Other candidates for "nontraditional inheritance"

1) Mitochondrial inheritance -- only from the mother in humans.
   There are several genetic diseases associated with mitochondrial
   genetic defects.  Mitochondria are energy-producing organelles with
   their own genome, and are inherited only from the mother in the
   vast majority of cases.

2) Imprinting
   Imprinting refers to a difference in a gene's effect dependent
   on which parent it was inherited from. 
   In some cases, genetic
   diseases occur in heterozygous individuals, because the locus
   is imprinted and the individual has the bad luck to inherit
   the functional copy from the parent whose contribution is turned off.

3) Uniparental disomy
   In some rare cases, a karyotypically-normal individual inherits both
   copies of a chromosome (or a large part of a chromosome) from the
   same parent.  

I'm sure someone out there can supply more...


Keith Robison
Harvard University
Department of Cellular and Developmental Biology
Department of Genetics / HHMI

robison at mito.harvard.edu