THE BLOOD GROUPS OF MARINE ANIMALS
109
varying with respect to the presence and absence of two antigens
(Cushing, 1966). The extensive research of Suzuki et al. and Sprague
et al. has greatly expanded our knowledge so that blood group polymorphism is now known to occur in complex patterns in several
well-known species.
Notable among the variety of agglutinogens found in tuna are those
of the Tgl, Tg2, TgO system in albacore (Thunnw germ) (Suzuki
et al., 1958, 1959), and those of the ABO system of bigeye (Thunnw
obema (Lowe)) (Sprague et al., 1962). Each of these systems determines
four phenogroups, the relative proportions of which conform in each
species in the North Pacific to the expectations for three allele systems
in Hardy-Weinberg equilibrium (Marr and Sprague, 1962 ; Sprague
et al., 1962). Suzuki and his associates have done extensive work to
show that albacore samples from the Indian Ocean differ markedly
from those taken in tho North Pacific Ocean with respect to their
Tg frequencies. The frequencies of samples from the Indian Ocean
are not in Hardy-Weinberg equilibrium (Marr and Sprague, 1962)
and bppear to consist of a mixture of populations that are different
from that in the North Pacific.
An additional antigen, Tg3, was useful in differentiating Atlantic
samples of albacore from those in the Indian and Pacific Oceans
(Suzuki, 1962a, b), and antigens with Tg and other specificities were
found in varying combinations in other species of tunas, notably the
bigeye and yellowfin (Suzuki, 1902a, b ; Suzuki and Moria, 1960;
Sprague et al., 1962).
Sprague et al. (1962) have recognized the probable occurrence of
an ABO system in albacore close to that of bigeye, and a second
system of subtypes C,, C,, C, that occurs in several species. This
system includes one of the antigens initially detected in skipjack by
normal bovine serum (Cushing, 1956). Similar systems have been
shown in the yellowfin by Sprague and Hunter (manuscript in prep.).
Skipjack have in addition to the C system, a second system which
includes at least three blood factors K,, K, and E (Sprague and
Holloway, 1962; Sprague et aE., 1962). The first two of these show a
subtype relation to each other, and the E factor seldom occurs in
Krpositive blood. Six different phenogroup patterns have been
identified with respect to these antigens, but their genetic relations
=main to be clarified. Table I1 shows that the proportions of K,,
K, and (‘”’ phenogroups differed significantly among samples from
the Hawaiian, Marquesas and Tuamotu-Society area. These differences
lead to the interpretation that at least two and probably three reproduct.ively isolated populations of skipjack were sampled. (The possi-
109
varying with respect to the presence and absence of two antigens
(Cushing, 1966). The extensive research of Suzuki et al. and Sprague
et al. has greatly expanded our knowledge so that blood group polymorphism is now known to occur in complex patterns in several
well-known species.
Notable among the variety of agglutinogens found in tuna are those
of the Tgl, Tg2, TgO system in albacore (Thunnw germ) (Suzuki
et al., 1958, 1959), and those of the ABO system of bigeye (Thunnw
obema (Lowe)) (Sprague et al., 1962). Each of these systems determines
four phenogroups, the relative proportions of which conform in each
species in the North Pacific to the expectations for three allele systems
in Hardy-Weinberg equilibrium (Marr and Sprague, 1962 ; Sprague
et al., 1962). Suzuki and his associates have done extensive work to
show that albacore samples from the Indian Ocean differ markedly
from those taken in tho North Pacific Ocean with respect to their
Tg frequencies. The frequencies of samples from the Indian Ocean
are not in Hardy-Weinberg equilibrium (Marr and Sprague, 1962)
and bppear to consist of a mixture of populations that are different
from that in the North Pacific.
An additional antigen, Tg3, was useful in differentiating Atlantic
samples of albacore from those in the Indian and Pacific Oceans
(Suzuki, 1962a, b), and antigens with Tg and other specificities were
found in varying combinations in other species of tunas, notably the
bigeye and yellowfin (Suzuki, 1902a, b ; Suzuki and Moria, 1960;
Sprague et al., 1962).
Sprague et al. (1962) have recognized the probable occurrence of
an ABO system in albacore close to that of bigeye, and a second
system of subtypes C,, C,, C, that occurs in several species. This
system includes one of the antigens initially detected in skipjack by
normal bovine serum (Cushing, 1956). Similar systems have been
shown in the yellowfin by Sprague and Hunter (manuscript in prep.).
Skipjack have in addition to the C system, a second system which
includes at least three blood factors K,, K, and E (Sprague and
Holloway, 1962; Sprague et aE., 1962). The first two of these show a
subtype relation to each other, and the E factor seldom occurs in
Krpositive blood. Six different phenogroup patterns have been
identified with respect to these antigens, but their genetic relations
=main to be clarified. Table I1 shows that the proportions of K,,
K, and (‘”’ phenogroups differed significantly among samples from
the Hawaiian, Marquesas and Tuamotu-Society area. These differences
lead to the interpretation that at least two and probably three reproduct.ively isolated populations of skipjack were sampled. (The possi-