Evolutionary Dynamics of the Alpha-actinin Gene Family
Abstract
The alpha-actinin gene family is a member of the spectrin superfamily of
proteins. Other members of this superfamily include the a- and ~-spectrins, ~heavy
spectrin and dystrophin. Each member of this superfamily has a unique actin
cross-linking distance consequent to the specific number of spectrin repeats
within the central repeat region of the superfamily. Alpha-actinin is thought to
be the least derived of the spectrin superfamily due to its possession of the
smallest number of spectrin repeats. Though many a-actinins are known, the
relationships among them are as yet undetermined. I performed phylogenetic
analyses on a-actinin sequences to establish the kinship among a-actinin
isoforms and to taxonomically treat the sequences. In addition, I sequenced and
analyzed a previously unknown rat a-actinin 3. Analyses support four main
isoforms of a-actinin. I also investigated homogenizing evolution within the
spectrin repeats of the gene family. This was accomplished using gene
conversion analyses and a new analysis which implements a continuum of the
two known modes of homogenizing evolution: birth-and-death evolution and
concerted evolution. This conceptual leap to a continuous model has not
previously been made. Furthering these generalized studies of the a-actinin
gene family, I used RT-PCR, cloning and automated DNA sequencing to obtain
77bp of sequence for what may be yet another member of the spectrin
superfamily, the G3.5 antigen.
Citation
Dixson, J. D. (2001). Evolutionary dynamics of the alpha-actinin gene family (Unpublished thesis). Southwest Texas State University, San Marcos, Texas.Download
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