Mw. Shirley, The genome of Eimeria spp., with special reference to Eimeria tenella - a coccidium from the chicken, INT J PARAS, 30(4), 2000, pp. 485-493
Eimeria spp. contain at least four genomes. The nuclear genome is best stud
ied in the avian species Eimeria tenella and comprises about 60 Mbp DNA con
tained within ca. 14 chromosomes: other avian and lupine species appear to
possess a nuclear genome of similar size. In addition, sequence data and hy
bridisation studies have provided direct evidence for extrachromosomal mito
chondrial and plastid DNA genomes, and double-stranded RNA segments have al
so been described. The unique phenotype of "precocious" development that ch
aracterises some selected lines of Eimeria spp. not only provides the basis
for the first generation of live attenuated vaccines, but offers a signifi
cant entree into studies on the regulation of an apicomplexan life-cycle. n
e With a view to identifying loci implicated in the trait of precocious dev
elopment, a genetic linkage map of the genome of E. tenella is being constr
ucted in this laboratory from analyses of the inheritance of over 400 polym
orphic DNA markers in the progeny of a cross between complementary drug-res
istant and precocious parents. Other projects that impinge directly or indi
rectly on the genome and/or genetics of Eimeria spp. are currently in progr
ess in several laboratories, and include the derivation of expressed sequen
ce tag data and the development of ancillary technologies such as transfect
ion techniques. No large-scale genomic DNA sequencing projects have been re
ported. (C) 2000 Published by Elsevier Science Ltd on behalf of the Austral
ian Society for Parasitology Inc. All rights reserved.