Vle CONG. INTERN. REPROD. ANIM. INSEM. ARTIF., PARIS, 1968, VOL. I

(Tables 2 and 3). These cases suggest that in these species
the Y chromosome is not essential for testicular development.
Such a conclusion appears to be in conflict with the conclusions
from studies on men and mice, where the Y chromosome is consi-
dered necessary (see Sohval, 1963). The conclusion also appears
to be in conflict with the biologically more general suggestion
of Beatty (1964) that the testes only develop in the hetero-
gametic sex. The data on man, however, is not completely clear-
cut as several cases are known with small testes and an XX
chromosome constitution. Also several true hermaphrodites are
known with only an XX chromosome constitution.

Ferguson-Smith (1966) has suggested that genetic material
from the Y chromosome may be transferred to the X chromosome
by crossing over. A second possible explanation is that trans-
location of the Y chromosome may occur, and that this cannot
be detected by standard cytological methods. A third explana-
tion has been suggested by McFeely, Hare and Biggers (1967) ,
based on studies of pseudohermaphroditism in the goat. This
intersexual condition is determined by a single recessive
autosomal gene. It is suggested that alleles of the male de-
termining genes are normally present in the X chromosomes but
in a repressed condition, and that in the presence of the auto-
somal mutant gene these alleles become derepressed, and allow

male characteristics to develop. All these suggestions assume

that Y genetic material is present in the intersexes. This

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