26
Database of Karyotypes: How to Use the Database
The database of fi sh karyotypes (Tables 4–7) is organized in the form of tables subdivided into 12
fi
columns (A to L) as follows.
1. Column A contains current scientifi c names of karyotyped taxon. Classifi
fi
cation of species,
fi
as a rule, followed Eschmeyer’s Catalogue of Fishes (E-13). Classifi cation of higher taxa than
fi
species, as a rule, followed Nelson (N-68). Hybrids were not included. Synonymy of species/
subspecies followed, as a rule, Eschmeyer (E-13).
2. Column B includes the names used in the original karyotype papers in cases in which these
differ from currently accepted classification. fi
3. Column C shows the sex of fishes studied. The majority of fi
fi
shes reproduce bisexually.
fi
However, sex chromosome systems unequivocally identifi ed by karyotypes are known only
fi
in a limited number of species. Datasets for such heterosomes were given separately for both
sexes and were marked with ‘F’ for females and ‘M’ for males. For possible further items,
see also column J.
4. Column D contains diploid chromosome number (2n), marked with an asterisk when
inferred from a haploid number. B chromosomes, as a rule, were excluded from diploid
chromosome number.
5. Column E includes the karyotype. Classification of chromosomes followed Levan et al. (L-25):
fi
M, metacentrics, SM, submetacentrics, ST, subtelocentrics, A, acrocentrics. When these could
not be clearly derived from source publications, classification was as follows: meta- and/or
fi
submetacentric (M/SM), submeta- and/or subtelocentric (SM/ST), and subtelo- and/or acrocentric (ST/A). Difference in the karyotype could be attributed to different degrees of chromosome condensation, leading to differences in chromosome classifi cation among authors.
fi
In karyotypes of cartilaginous fishes and ancient fi
fi
shes such as lobe-fi
fi
nned, acipenseriform,
fi
and lepisosteiform fishes, small dot-like microchromosomes (MC) have been observed. They
fi
are so small that they could not be identified to any type of chromosomes defi
fi
ned by Levan
fi
et al. (1964: L-25) at present. It is unknown whether MC is different from M, SM, ST, and A.
In this book, MC was added as an additional type to M, SM, ST, and A. As for papers in which
the description of karyotype disagrees with the figures, karyotypes based on the fi
fi
gures, as
fi
a rule, were adopted.
6. Column F (NF 1 ) shows fundamental arm number, when M and SM are counted as
two-armed.
7. Column G (NF 2 ) contains fundamental arm number, when M, SM, and ST are counted as
two-armed. The arm number by Scheel (1972: S-24) differs from NF 2 . As Scheel counted all
chromosomes with a short arm as two-arms, acrocentrics with short arms were counted as
two-arms, i.e., NF sensu Scheel ≥ NF 2 . Therefore, Scheel’s arm number is shown in
parentheses.
8. Column H includes the number of Ag-NORs. The number and position of NORs can differ
by different methods such as chromomycin A 3 and silver staining. Silver staining is the
method specific to NORs and studied widely. The number of Ag-NORs in the embryo tends
fi
to be larger than that of adults. Recently, 18S rDNA and 5S rDNA, which are components of
NORs, have been examined by fluorescence in situ hybridization (FISH). However, the number
fl
of species for which NORs have been studied by FISH is limited.
9. Column I shows genome size (pg/cell). Following Gregory (G-85), the methods used to
estimate genome size were listed in fi ve categories: fl
fi
ow cytometry (FCM), Feulgen densifl
tometry (FD), Feulgen image analysis densitometry (FIA), bulk fluorometric assay (BFA),
fl
and static cell fluorometry (SCF). To facilitate comparison of genome size (pg/cell), the
fl
genome sizes of standard species were updated according to Gregory (G-85): Acipenser
ruthenus (3.8 pg), Carassius auratus (3.5 pg), Cyprinus carpio (3.4 pg), Gallus domesticus
Database of Karyotypes: How to Use the Database
The database of fi sh karyotypes (Tables 4–7) is organized in the form of tables subdivided into 12
fi
columns (A to L) as follows.
1. Column A contains current scientifi c names of karyotyped taxon. Classifi
fi
cation of species,
fi
as a rule, followed Eschmeyer’s Catalogue of Fishes (E-13). Classifi cation of higher taxa than
fi
species, as a rule, followed Nelson (N-68). Hybrids were not included. Synonymy of species/
subspecies followed, as a rule, Eschmeyer (E-13).
2. Column B includes the names used in the original karyotype papers in cases in which these
differ from currently accepted classification. fi
3. Column C shows the sex of fishes studied. The majority of fi
fi
shes reproduce bisexually.
fi
However, sex chromosome systems unequivocally identifi ed by karyotypes are known only
fi
in a limited number of species. Datasets for such heterosomes were given separately for both
sexes and were marked with ‘F’ for females and ‘M’ for males. For possible further items,
see also column J.
4. Column D contains diploid chromosome number (2n), marked with an asterisk when
inferred from a haploid number. B chromosomes, as a rule, were excluded from diploid
chromosome number.
5. Column E includes the karyotype. Classification of chromosomes followed Levan et al. (L-25):
fi
M, metacentrics, SM, submetacentrics, ST, subtelocentrics, A, acrocentrics. When these could
not be clearly derived from source publications, classification was as follows: meta- and/or
fi
submetacentric (M/SM), submeta- and/or subtelocentric (SM/ST), and subtelo- and/or acrocentric (ST/A). Difference in the karyotype could be attributed to different degrees of chromosome condensation, leading to differences in chromosome classifi cation among authors.
fi
In karyotypes of cartilaginous fishes and ancient fi
fi
shes such as lobe-fi
fi
nned, acipenseriform,
fi
and lepisosteiform fishes, small dot-like microchromosomes (MC) have been observed. They
fi
are so small that they could not be identified to any type of chromosomes defi
fi
ned by Levan
fi
et al. (1964: L-25) at present. It is unknown whether MC is different from M, SM, ST, and A.
In this book, MC was added as an additional type to M, SM, ST, and A. As for papers in which
the description of karyotype disagrees with the figures, karyotypes based on the fi
fi
gures, as
fi
a rule, were adopted.
6. Column F (NF 1 ) shows fundamental arm number, when M and SM are counted as
two-armed.
7. Column G (NF 2 ) contains fundamental arm number, when M, SM, and ST are counted as
two-armed. The arm number by Scheel (1972: S-24) differs from NF 2 . As Scheel counted all
chromosomes with a short arm as two-arms, acrocentrics with short arms were counted as
two-arms, i.e., NF sensu Scheel ≥ NF 2 . Therefore, Scheel’s arm number is shown in
parentheses.
8. Column H includes the number of Ag-NORs. The number and position of NORs can differ
by different methods such as chromomycin A 3 and silver staining. Silver staining is the
method specific to NORs and studied widely. The number of Ag-NORs in the embryo tends
fi
to be larger than that of adults. Recently, 18S rDNA and 5S rDNA, which are components of
NORs, have been examined by fluorescence in situ hybridization (FISH). However, the number
fl
of species for which NORs have been studied by FISH is limited.
9. Column I shows genome size (pg/cell). Following Gregory (G-85), the methods used to
estimate genome size were listed in fi ve categories: fl
fi
ow cytometry (FCM), Feulgen densifl
tometry (FD), Feulgen image analysis densitometry (FIA), bulk fluorometric assay (BFA),
fl
and static cell fluorometry (SCF). To facilitate comparison of genome size (pg/cell), the
fl
genome sizes of standard species were updated according to Gregory (G-85): Acipenser
ruthenus (3.8 pg), Carassius auratus (3.5 pg), Cyprinus carpio (3.4 pg), Gallus domesticus