Genetics. Published Articles Ahead of Print: October 18, 2007, Copyright © 2007
doi:10.1534/genetics.107.075689


A more recent version of this article appeared on December 1, 2007.

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Differential Effect of Allorecognition Loci on Phenotype of Hydractinia symbiolongicarpus (Cnidaria: Hydrozoa) and Its Effect on Phenotype

Anahid E. Powell 1*, Matthew L. Nicotra 1, Maria A. Moreno 1, Fadi G. Lakkis 2, Stephen L. Dellaporta 1 and Leo W. Buss 1

1 Yale University
2 University of Pittsburgh School of Medicine

* To whom correspondence should be addressed. E-mail: anahid.powell{at}yale.edu.

Submitted on June 8, 2007
Revised on June 27, 2007
Accepted on 24 September 2007


Abstract

The allorecognition complex of Hydractinia symbiolongicarpus is a chromosomal interval containing two loci, alr1 and alr2, that controls fusion between genetically distinct colonies. Recombination between these two loci has been associated with a heterogeneous class of phenotypes called transitory fusion. A large-scale backcross was performed to generate a population of colonies (N=106) with recombination breakpoints within the allorecognition complex. Two distinct forms of transitory fusion were correlated with reciprocal recombination products, suggesting that alr1 and alr2 contributed differentially to the allorecognition response. Specifically, type 1 transitory fusion is associated with rapid and persistent separation of allogeneic tissues, whereas type 2 transitory fusion generates a patchwork of continuously fusing and separating tissues.

Key Words: allogeneic recognition, fusion, hydroid, rejection, transitory fusion