Chromosome Studies on Trillium kamtschaticum Pall

XIII. The structure and behavior of the kinetochore

Abstract

1) It is pointed out that the kinetochore is subjected to variable effects under different treatments and this has caused much serious confusion in terminology of this cell organ. The writer prefers the term “kinetochore” for this organ rather than the other current name “centromere”, because it proved to be not of such a chromomeric nature as the latter name implies.
2) The kinetochore is a compound body consisting of the chromonematic thread (=the kinetonema) which is persistent throughout the division and of the matrix surrounding it which develops fully at metaphase.
3) The behavior of the kinetonema is just the same as that of the rest of the chromonema (=the genonema), viz., in pairing, in opening-out, in separation of the daughter halves and in the development of the matrix, excepting that the genonema is always precocious in behavior as contrasted with the kinetonema under usual conditions.
4) The origin of the so-called “Zugfasern” is inferred to be such as previously advocated by Belar; they arise from the kinetochore toward the pole and not in the reverse direction.