Biology Reference
In-Depth Information
FIGURE 8.2. Paint-filled inner ears showing two types of malformation. (A) and (C)
are controls at the same age as the mutants (B) and (D), respectively. (B) This
mutant, one day after birth, shows a truncation of the lateral canal, shown by the
asterisk. (D) The mutant represented, embryonic day 14.5, shows complete lack of
development of the semicircular canals. The vestibular part of the inner ear remains
as a cyst-like structure, and the endolymphatic sac (es) is enlarged. ssc, superior
semicircular canal; psc, posterior semicircular canal; lsc, lateral semicircular canal;
ut, utricle; sac, saccule; cd, cochlear duct; es, endolymphatic sac; cc, crus commune.
activity (Kiernan et al. 1999). Furthermore, as for outer and middle ear
defects, many of the knock-out mutants show early death, precluding
assessment of cochlear function by most standard physiological approaches;
cochlear function can be first detected at around twelve days after birth in
normal mice.
