Artificial yeast chromosomes (YACs)

Large DNA fragments (200–300 kb) can be replicated
in yeast cells. They are inserted into artificial
yeast chromosomes (YAC, see p. 110) and
replicated with them. A photograph of a transverse
alternating field electrophoresis (TAFE)
with nine lanes after ethidium bromide staining
shows fragments of different sizes. These correspond
to the naturally occurring yeast chromosomes.
Six of the lanes (2–7) contain an additional
band, which corresponds to an artificial
yeast chromosome. They are marked with a yellow
point: the lowest band in lane 2 (YAC9), the
third band from the bottom in lanes 3, 4, and 6
(YAC41, YAC45, YAC51), and the lowest band in
lane 7 (YAC52). In lane 5, YAC50 is masked by a
yeast chromosome (third fragment from
below).