Download Establishment of an Albino Strain of the Bitterling Tanakia signifer

Journal of Heredity 2007:98(3):277–279
doi:10.1093/jhered/esm016
Advance Access publication April 2, 2007
ª The American Genetic Association. 2007. All rights reserved.
For permissions, please email: [email protected].
Establishment of an Albino Strain of
the Bitterling Tanakia signifer (Pisces,
Cyprinidae)
T. UEDA, T. ISHINABE,
AND
S-R. JEON
From the Department of Biology, Faculty of Education, Utsunomiya University, 350 Mine, Utsunomiya 321-8505, Japan
(Ueda); the Kannonzaki Nature Museum and Institute, 4-1120 Kamoi, Yokosuka 239-0813, Japan (Ishinabe); and the
Department of Biology, College of Natural Science, Sang Myung University, Jongno-gu, Hongji-dong 7, Seoul 110-743,
Korea (Jeon).
Address correspondence to T. Ueda at the address above, or e-mail: [email protected].
An albino strain of the bitterling Tanakia signifer (Pisces,
Cyprinidae, Acheilognathinae) was established through interbreeding using an albino male selected from among the offspring produced from the spawning of 18 wild-caught
individuals. This is the first report of albinism in this species.
Progeny tests demonstrated that inheritance of the trait follows the expected pattern for a simple autosomal recessive.
A stock of 200þ individuals is currently being held at the
Kannonzaki Nature History Museum, Japan.
The Acheilognathinae, or bitterlings, to which Tanakia signifer
(Pisces, Cyprinidae) belongs, consists of three genera, Tanakia, Acheilognathus, and Rhodeus (Arai and Akai 1988). The approximately 50 species and subspecies are widely distributed
in Eurasia, with most occurring in East Asia (Nakamura 1969;
Choi et al. 1990; Holcik and Jedlicka 1994; Lin 1998). Tanakia
signifer, which is distributed only in the Korean Peninsula,
is closely related to Tanakia tanago, which is distributed in
Tochigi and Chiba Prefectures, Japan (Okazaki et al. 2001).
The group of bitterlings is characterized by a unique reproductive behavior in which females use an ovipositor to lay
their eggs inside the gills of freshwater bivalves where the
larvae develop (Nakamura 1969).
The propagation of bitterlings is also closely related to
agricultural activities because many bitterling species thrive
in irrigation canals. They have constantly adapted to secondary environment induced by humans. However, the environment of the irrigation canals has changed as a result of
changes in human life styles in the latter half of 20th century.
Consequently, bitterling species facing extinction have been
increasing markedly in number. Also, recently, the wild Tanakia signifer population has been decreasing.
Studies of bitterlings have been numerous and include
fields such as genetics, embryology, ethology, and environmental education (Ueno and Arimoto 1982; Suzuki et al.
1986; Ohta 1991; Ueda 1996; Kanoh 2000; Kawamura
and Hosoya 2000; Saitoh et al. 2000; Sola et al. 2000; Okazaki
et al. 2001; Ueda et al. 2001; Smith et al. 2004; Kawamura
2005). The occurrence of albinism, which is a useful genetic
marker in basic research on chromosome manipulation, has
been reported in some fishes (Bridges and Limbach 1972;
Yamamoto and Oikawa 1973; Kirpichnikov 1981; Rothbard
and Wohlfarth 1993; Thorgaard et al. 1995) but has not been
previously reported in bitterlings.
An albino strain of the bitterling T. signifer was established
with natural mating with freshwater bivalves and artificial fertilization without bivalves in the laboratory. Eighteen wildphenotype individuals were collected from the Imgye river
in the Namhan river system in Gangweon Province, South
Korea, in 1998. In 1999, an albinistic male, characterized as
having red eyes and a lack of melanin in the chromatophores,
was selected from about 30 000 individuals reproduced. In
2000, about 200 individuals (F1) were reproduced from
crosses of wild-phenotype females an albino-phenotype
male, and all of them were wild phenotype. The sex ratio
was approximately 1:1. In 2001, about 50 albino-phenotype
individuals (F2) were selected from about 100 individuals
from crosses of female F1 an albino-phenotype male. In
2002, about 200 albino-phenotype individuals were selected
from crosses of F2 F1. In 2003–2005, albino-phenotype individuals were kept from crosses with only albino-phenotype
individuals. These individuals were allowed to mature for
a year. They spawn only in spring. Fry were fed with pounded
fish food and living brine shrimp.
To understand how albinism is inherited, we undertook
breeding tests using artificial fertilization. The numbers of
albino-phenotype and wild-phenotype individuals obtained
from 19 crosses are shown in Table 1. Six albino-phenotype
(A1, A2, A3, A4, A5, and A6) and 4 wild-phenotype individuals (W1, W2, W3, and W4) were used in crosses numbers
1–15. Both sexes were found in the offspring from crosses of
wild-phenotype albino-phenotype individuals (cross numbers 12–15). This supports the hypothesis that albinism is an
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Journal of Heredity 2007:98(3)
Table 1. Inheritance of albinism in Tanakia signifer
No. of individuals
Albino phenotype
Crosses [genotypes]
Cross no.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
$#
[nn nn]
A1 A2
A1 A2
A1 A2
A1 A3
A1 A4
A5 A2
A5 A3
A5 A4
A6 A2
A6 A3
[NN NN]
W1 W2
[nn NN]
A1 W2
A5 W2
[NN nn]
W3 A2
W4 A2
[Nn Nn]
(W3 A2)1
(W3 A2)3
(W3 A2)3
(W3 A2)6
$
#
?
$
#
?
9
8
5
7
5
7
6
3
5
5
3
3
0
2
1
1
1
0
0
1
3
2
0
1
1
2
1
0
0
2
0
1
3
2
0
0
1
2
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
25
0
0
0
6
6
5
8
6
0
0
0
0
0
0
3
1
2
2
1
0
22
17
0
0
0
0
0
0
4
3
4
4
7
4
8
6
6
6
1
1
0
0
1
0
0
1
0
0
0
0
1
1
2
0
2
1
1
0
0
1
0
1
No. of used eggs
(W3
(W3
(W3
(W3
A2)2
A2)4
A2)5
A2)7
Wild phenotype
A: albino phenotype; W: wild phenotype; and ?: the sex was unknown.
autosomal character. Further, the observation that all 35 individuals were wild phenotype strongly suggests that the albinism is a recessive character.
All the offspring from cross 14 were wild phenotype. We
selected the parents of crosses numbers 16–19 from the offspring of cross 14 and assumed they had the heterozygote
genotype of albinism, Nn (N, dominant gene; n, recessive
gene) with wild phenotype. The genotypes in each cross are
regarded as nn nn (nos 1–10), NN NN (no. 11), nn
NN (nos 12–13), NN nn (nos 14–15), and Nn Nn
(nos 16–19), respectively, from examination on 5% significant level by chi-square test (Table 1).
If the albinism is inherited as a simple autosomal recessive
character, individuals from numbers 16 to 19 crosses are expected at a 3:1 ratio of wild to albino phenotype. Ten wildphenotype and 4 albino-phenotype individuals were produced
from our crosses. Significant evidence that this ratio is not
3:1 is not recognized on 5% significant level by chi-square
test. Therefore, from these results, we conclude that albinism
in T. signifer is inherited as a simple autosomal recessive
character.
A stock of 200þ albinistic individuals is currently being
held at Kannonzaki Natural History Museum, Japan.
Scientific Research [B(2)10041156 and B(1)12575009] from the Ministry of
Education, Science, Sports and Culture, Japan, for Research from Japan Fisheries Resource Conservation Association, Japan, and for Eminent Research
at Utsunomiya University, Japan.
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Received June 7, 2006
Accepted November 30, 2006
Corresponding Editor: Lisa Seeb
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