A marker can be combined with another marker by selecting the
Composite checkbox which will enable the
secondary marker tab. If the Overlay checkbox
is selected, the primary and secondary markers will be positioned so
that their origins coincide, otherwise the secondary marker will be
offset from the primary marker (see also Marker
Offset below). Figure 9.8 shows two
examples of composite markers: in Figure 9.8(a) the
start and end markers are formed from a pointed arrow primary marker
of size 5 and a composite bar secondary marker, while in
Figure 9.8(b) the start and end markers are formed
from an open semicircle primary marker of size 5bp with an overlaid
reversed filled semicircle secondary marker of size 5bp.
Figure 9.8:
Examples of composite
markers: (a) a bar primary marker with a pointed secondary
marker of size 5bp; (b) an open semicircle primary marker of
size 5bp overlaid with a reversed filled semicircle secondary marker
of size 5bp.