SIR,- We note in your leading article of April 4 a genuine
misunderstanding of a simple French word. Referring to our paper (1), you say
that " it is fairly certain that this extra chromosome is the result of
tripling of one of the normal pairs, and not, as Lejeune et al. call it, a
supernumerary in the true sense of something quite extraneous to the normal
complement " (our italics).
We had in fact described a " chromosome supplémentaire " in mongolian
cells. The French words " supplémentaire " and " sumuméraire " (the latter
used in our second paper (2)) do not mean " something quite extran-eous to the
normal complement", but merely " supplementary " or " supernumerary ".
Examination of our second note to the Academic des Sciences on March 16,
reporting nine cases of mongolism with a " supplementary " or " supernumerary "
chromosome, would have avoided such a misunderstanding. In this note we raise
the hypothesis of the non-disjunction of a small telocentric pair as an
explanation of the " supernumerary " chromosome.
The linguistic troubles are more surprising since Ford et al. (3) and
Jacobs et al. (4) felt there was no ambiguity attached to the term, which they
translate by extra, additional, or supernumerary.
Finally it is entirely true that we have "for reasons so far
unspecified, also thought it worth investigating mongolism ". It passes our
imagination that a supposedly well-authorised critic should naïvely wonder
about the reasons leading to scientific achievements.
We should be grateful if we could extend through your columns our
appreciation to Dr. Ford and to Dr. Court Brown for their kindness in informing
us, before publication, of their beautiful work which confirms our
1. Lejeune, J., Gautier, M., Turpin, R. C.R. Acad. Sci., Paris, Jan.
26, 1959, 248, 602.
2. Lejeune, J., Gautier, M., Turpin, R. ibid. March 16, 1959, p.
3. Ford, C. E., Jones, K. W., Miller, O. J., Mittwoch, U., Penrose, L.
S., Ridler, M., Shapiro, A. Lancet, April 4, 1950, p. 709.
4. Jacobs, P. A., Baikie, A. G., Court Brown, W. M., Strong, J. A.
ibid. p. 710.
5. White, M. J. D. Animal Cytology and Evolution; p. 156 et seq.
The term " supernumerary chromosome " is used loosely by some to mean
any kind of additional chromo-some, but increasingly in the restricted sense
(5) in which we employed it. Of the papers in our issue of April 4, one (4)
uses it in the restricted sense, one (3) uses it more loosely. We were clearly
wrong in translating Dr. Lejeune and his colleagues (5) term as " supernumerary
", and in assuming that they might be using the word in the restricted sense we
went further astray. Their second paper, (2) which was not available to us
three weeks ago, makes this quite clear, and indicates that they are in
substantial agreement with the British workers as to the probable nature of the
We can assure our French colleagues that no criticism lay behind our
inquisitiveness about the reasons which