Nomenclature for centromeric position on chromosomes

TLDR: At the present time, with the immense increase in research activity in mammalian cytology, the terminology of the centromeric position has become burdened by much obscurity and confusion.

Abstract: N the inorphologic identification of chromosomes, the location of the I centromere is the most useful landmark, and one which is characterized by great constancy. It would seem that not much could be added to the definitions by E. B. WILSON (1928) of the locations on the chromosome of the centrornere or, in the terminology of that time, the spindle attachment: “Attachment of the chromosome to the spindle is commonly limited to a small area, and is of two general types, namely: (1) terminnl or telomitic and (2) non-ferminal or atelomitic, being in the former case at one end, and in the latter at some other point or points. Non-terminal attachment may be at the middle point (median) or at an intermediate point (submedian, sub-terminal). All gradations exist between these various cases;” (I.c., p. 130-131). In the acconipanying picture (l.c., Fig. 56, p. 132), here reprinted as Fig. l., the four locations of median, submedian, subterminal and terminal are represented, and, in addition, “lateral”, which corresponds to the modern term “diffuse centromere”. Nevertheless, at the present time, with the immense increase in research activity in mammalian cytology, the terminology of the centromeric position has become burdened by much obscurity and confusion. One cause of confusion is that different authors, and even the same author on different occasions, have used the terms median, submedian etc. with great amplitude, and it is often difficult to know in a specific case what each term signifies. Another cause of confusion is that a set of terms for chromosomes with specific centromeric positions, such as metacentric, acrocentric, telocentric, have come into wide usage without being clearly defined in relation to the positional terms median, submedian, subterminal and terminal. During the spring of 1963 the present writers exchanged epistolary