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6. DO ANY SPECIES BOUNDARIES....
6.3.2. Genetic map of L. multiflorum and L. perenne
Genetic map was constructed based on the most polymorphic interspecific population
i.e., the F 2
population derived from the cross between L. multiflorum cultivar Bartolini, BR3
and L. perenne ecotype from New Zealand, NZ15. The final linkage map covered 1014 cM
and consisted from 502 loci including 484 DNA markers, 16 enzymatic loci and two different
loci responsible for seedling root fluorescence, SRF (Table 6.7). Among DNA markers
(Figure 6.4), RAPD and AFLP markers were the most abundant (132 and 137, respectively),
following by transposon-based markers, SSAP (96) and Intron Splice Junction markers, ISJ
(80). It was also possible to map markers amplified by primers complementary to M. tuberculosis
insertion element IS6110 (IS markers) and KatG gene encoding bacterial catalaseperoxidase
(katG markers).
All mapped markers gave rise to seven linkage groups (Figure 6.5A-G) presumably
corresponding to the seven chromosomes of Lolium. These groups were numbered using
the numerical order from LG1 to LG7, which was as much as possible in agreement with the
first genetic map published by Hayward et al. (1998). The linkage groups covered from 92.7
to 214.2 cM and consisted from 46 to 91 markers (Table 6.7). The LG1 of 214.2 cM in length
with 86 markers mapped was the longest among all groups (Figure 6.5A). It corresponded to
the first linkage group of Hayward et al. (1998) owing to common enzymatic loci, Est4, Aat2,
Sod1 and Pgdh1. The presence of the majority of markers amplified by primers complementary
to M. tuberculosis insertion element IS6110 and as many as five enzymatic loci were
unusual features of this group. The LG2 (Figure 6.5B), the second group with regard to the
length (183.7 cM) but the first with regard to the number of markers mapped also correspond-