Page 2 - Mantovani_alii_1999

266 B. MANTOVANI, M. PASSAMONTI, V. SCALI

Downloaded by [31.185.101.115] at 11:07 10 April 2016 ® B. rossius O B. whitei
• B. fynceorum
O B. grandit grandii
• B. gmndii benazzii •ù B. rossius-grandii grandii
@ B. grandii maretimi •k B. rossius-grandii benazzii

H B. atticus atticus
D B. atticus cyprius
0 B. atticus carius

Fig. 1 - Map of the Mediterranean Basin showing Bacillus taxa distribution.

sius x B. grandii crosses. On the contrary, the route nents for the triploid hybrid (Mantovani et al, 1992;
leading to the triploid B. lynceorum is uncertain. A first
hypothesis suggested that this taxon is the product of Manaresi et al, 1993)-
backcrosses of B. whitei females ÇB. rossius/grandii The varied array of approaches so far mentioned, be-
grandii) to B. grandii grandii males (Bullini et al.,
1984). Subsequent allozymatic and karyological analy- sides clarifying phyletic relationships among Bacillus
ses suggested the contribution of the unisexual B. atti- taxa, also highlighted - although indirectly - the rate of
cus, in addition to the rossius/grandii grandii compo- evolution of specific nuclear genomic components.

More recently, the analysis of highly repeated nuclear
sequences (satellite DNA) and of a mitochondrial coding

B.whitei W B.rossius K B.rossius-grandii grandii
Bag320 \ (2n-35$)
1/ B.grandii grandii Bag32Q
B.lynceorum
(3n = 519) \ Bag320 B.rossius-grandii benazzii
(2n = 35?)
Bag32Q B.grandii benazzii Bag320
(2n = 34$;33c?)

5a^320

B.atticus
(2n = 34$)

Bag32Q

Fig. 2 - Schematic figure showing the origin of the unisexual taxa of the genus Bacillus from the parental species. It can be noted that
the Bag320 satellite DNA family is present in the bisexual B. grandii, in the automictic parthenogen B. atticus, and in all hybrids. The
same satDNA family is lacking in the bisexual B. rossius (thin arrows) (from Mantovani, 1998).