Genetic linkage map of E. tenella

A genetic linkage map of Eimeria tenella has been constructed through analyses of the inheritance of polymorphic DNA markers [amplified fragment length polymorphic (AFLP) markers; randomly amplified polymorphic DNA (RAPD-PCR) markers and restriction fragment length polymorphic markers (RFLP) markers] in 22 cloned progeny derived from a cross between a precocious line (faster developing) and a line resistant to the anticoccidial drug arprinocid.

Over 10000 DNA fragments in total have been resolved from which 443 polymorphic markers were scored (ca 4.4%). These markers have been assigned to 16 linkage groups, which comprise:

• markers that link together and can be assigned to specific chromosomes (achieved by hybridisation or linkage to the inheritance patterns of whole polymorphic chromosomes separated by PFGE)
• markers known to be derived from the same chromsosomes as some of the above groups, but which do not show statistical linkage with them

Around one third of the markers (over 130) have been placed in groups that were unlinked. Some of the groups contain up to 11 markers and may therefore be candidates to define the remaining chromosomes (not accounted for by the 16 major groups described above).

Other unassigned linkage groups are likely to be brought in to the map in due course, either through the identification of further intermediate linkage groups or from the results of hybridisation of representative probes to the molecular karyotype.

Data for the genetic linkage map are presented in different ways.

• Tables of all markers that show linkage at minimum LOD scores of 3
• Linkage maps of all markers that show linkage at minimum LOD scores of 3