Table I
The Base Composition of Iholeolar and Cytoplasnio RNA in Young
and in Large Starfish Oocytes
Young oooytes
diam. 45-55u adenine guanine cytoeine uracil
Animal no.
Nuoleoli I 21.8 30.6 27.8 19-Y
II 22.9 32.1 24.7 20.2
III 23.2 32.0 24.4 20.5
IV 23.0 31.4 26.0 19.4
Bean 22.7 31.5 25.7 20.0
Cytoplasm I 24.1 30.2 25.7 20.0
II 23.6 30.1 26.2 20.1
III 23.1 32.8 23.7 20.6
IV 22.6 31.1 25.4 20.3
mean 23.4 31.1 25.3 20.3
Large oooytes
diam. 80-110 u
adenine guanine cytosine uracil
Animal no.
Nucleoli V 23.7 33.4 2403 18.5
VI 22.2 34.1 27.5 16.2
VII 24.3 33.9 24.1 17.7
mean 23.4 33.8 25.3 17.5
Cytop+sm v 23.5 31.9 24.8 19.7
VI 23.6 30.9 27.1 18.5
VII 24.9 31.7 24.9 18.5
8ean 24.0 31.5 25.6 18.9
two componenta and shows great variations from animal to animal
(Table II).
The present renulta are oompatible with the notion that
the larger psrt of the oytopleamio RNA derives from the moleolus,
sinoe differenoee in base compoeition are found only
in late growth etagee when the nuoleolus is about to disappear.
The oause of the ohange in nuoleolar BNA oompoeition is unknown
and my be the result either of ohanged proportions
between different BNA fraotions, known to exist here (Vinoent,
1954; Sibatani et al. 19621 Adams and Busoh, lY62), or of