b chromosome number variability in the korean field mouse apodemus peninsulae (rodentia) from the...
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B CHROMOSOME NUMBER VARIABILITY IN
THE KOREAN FIELD MOUSE APODEMUS
PENINSULAE (RODENTIA) FROM THE RUSSIAN FAR
EAST
G.V. Roslik, I.V. Kartavtseva Institute of Biology and Soil Science of Far-Eastern
Branch of Russian Academy of Sciences, Vladivostok, Russia
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Apodemus peninsulae Thomas, 1906 is a polytypic species which widely distributed from East Siberia and North Mongolia, China to the Russian Far East,
Korea and Japan (Hokkaido)
- our data
- literature data
Photo by I. Kartavtseva
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The standard chromosome setThe standard chromosome setof the Korean field mouse, of the Korean field mouse, Apodemus peninsulaeApodemus peninsulae contains contains 48 acrocentric chromosomes48 acrocentric chromosomes and supernumerary chromosomes varying in number from 0 to 30 - in Siberia and from 0 to 7 in the Russian Far East.The B chromosomes (Bs) also had variations in size (from big to small) and in morphology – from macro to micro Bs (more frequently meta-, submetacentrics and micro Bs and rare subtelo-, acrocentrics and mini Bs)
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The levels of B chromosome’s The levels of B chromosome’s system variability in system variability in A. peninsulae:A. peninsulae:
• intrapopulational,intrapopulational,
• Interpopulational,Interpopulational,
• tissue, or individual (mosaicism),tissue, or individual (mosaicism),
• and variability of B’s differential staining. and variability of B’s differential staining.
55
THE AIM OF THE WORK WASTHE AIM OF THE WORK WAS::
• To study mosaicism on B To study mosaicism on B chromosome of the Korean chromosome of the Korean
field mouse field mouse Apodemus Apodemus peninsulae peninsulae fromfrom the Russian the Russian
Far EastFar East
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MATERIAL OF THE MATERIAL OF THE STUDY STUDY OFOFApodemus peninsulaeApodemus peninsulae Thomas Thomas 1906 1906
• The intra individual The intra individual mosaicism of Bs was study mosaicism of Bs was study in 355 animals collected at in 355 animals collected at 41 continental natural 41 continental natural localities of the Russian Far localities of the Russian Far East. East.
• There were specimens: There were specimens: from Magadan, Amur, from Magadan, Amur, Jewish and Khabarovsk Jewish and Khabarovsk Regions (n=87),Regions (n=87),
• and also from Primorskiy and also from Primorskiy Region (n=268).Region (n=268).
DISTINGUISHING OF MOSAICSDISTINGUISHING OF MOSAICSMosaicism was evaluated on the basis of the Mosaicism was evaluated on the basis of the number of cellular clones. number of cellular clones. Mosaics had two and Mosaics had two and more clones.more clones.Cellular clone - this is group of cells with the Cellular clone - this is group of cells with the definite number of chromosomes.definite number of chromosomes.
Cellular clones are isolated employing procedure Cellular clones are isolated employing procedure D.K. Belyayev with co-authors (1974);D.K. Belyayev with co-authors (1974); and number and number of cells analysed was determined according E.B. of cells analysed was determined according E.B. Hook (1977).Hook (1977).CClones are determined lones are determined aas the groups of the cells, s the groups of the cells, when the hypowhen the hypoploidploid class composes 10% and class composes 10% and more, and hypermore, and hyperploidploid - more or is equal to 5% - more or is equal to 5% (from the modal number of chromosomes)(from the modal number of chromosomes)..
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Frequency of intra individual Frequency of intra individual mosaicism of Bsmosaicism of Bs
• The wood mice have very frequentThe wood mice have very frequent occurrence of B chromosomes. It was found occurrence of B chromosomes. It was found that 312 that 312 (87.9 %)(87.9 %) animals possessed animals possessed B B chromosomeschromosomes. .
• 219 219 (61.7 %)(61.7 %) were were mosaicsmosaics with from two to with from two to five cellular clones andfive cellular clones and
• only 136 (only 136 (38,3%)38,3%) mice had mice had stable stable karyotypes.karyotypes.
99
MOSAICISM IN DIRRERENT MOSAICISM IN DIRRERENT POPULATIONS of POPULATIONS of A. peninsulae: A. peninsulae:
a–Khabarovsk Reg., b – Primorskiy Reg.a–Khabarovsk Reg., b – Primorskiy Reg.Evoron Lake -total (2001, 2002),
n=16 19%
6%
75%stable with Bs stable wihtout Bs mosaics
MagadanMagadan RegionRegion
AmurAmur RegionRegion
JewishJewish RegionRegion
Khabarovsk RegionsKhabarovsk Regions
Primorskiy RegionPrimorskiy Region
Borisovskoye plateau, n=813%
25%62%
stable with Bs stable wihtout Bs mosaics
Evoron Lake -total (2001, 2002), n=16 19%
6%
75%stable with Bs stable wihtout Bs mosaics
Borisovskoye plateau, n=813%
25%62%
stable with Bs stable wihtout Bs mosaics
Evoron Lake -total (2001, 2002), n=16 19%
6%
75%stable with Bs stable wihtout Bs mosaics
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MOSAICISM AT THE SAME MOSAICISM AT THE SAME POPULATION IN DIFFERENT YEARSPOPULATION IN DIFFERENT YEARS
Ussuriyskiy Res.-1996, n=26
57%14%
29%
stable with Bs stable without Bs mosaics
Ussuriyskiy Res. -1990, n=1030%
30%
40%
stable with Bs stable without Bs mosaics
Ussuriyskiy Res. - total (1987, 1989,1990, 1992,1995-1999), n=74
40%
19%
41%
stable with Bs stable without Bs mosaics
Ussuriyskiy Res.- 1999, n=138%
46%
46%
stable with Bs stable without Bs mosaics
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THE OCCURRENCE OF MOSAICSTHE OCCURRENCE OF MOSAICSMagadan, Jewish and Amur
Regions, n=200
30
70
without Bs stable,with Bs mosaics
Khabarovsk Region, n=67
22,4
16,4
61,2
without Bs stable,with Bs mosaics
Primorsky Region, n=268
10,4
28,4
61,2
without Bs stable,with Bs mosaics
The Russian Far East, total n=355
12,1
26,261,7
without Bs stable,with Bs mosaics
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SPECTRA OF Bs NUMBER SPECTRA OF Bs NUMBER VARIATIONVARIATION
01020304050607080
0 1 2 3 4Number of B chromosomes
Portio
n of sp
ecime
ns, %
MR-JR (n = 6) KHR (n = 26) PR (n = 104)
0
5
10
15
20
25
0-1 0-2 0-3 0-4 0-5 1-2 1-3 1-4 1-5 2-3 2-4 2-5 3-4 3-5 3-6 4-5 4-7 5-7Spectra of B chromosome variation
Po
rtio
n o
f sp
ec
ime
ns
, %
PR (n = 164) AR-JR (n = 14) KHR (n = 41)
MR – Magadan Region, AR – Amur Region,JR – Jewish Region, KHR – Khabarovsk Region,PR – Primorskiy Region;n - number of specimens.
Stable
Mosaics
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METAPHASES WITH DIFFERENT METAPHASES WITH DIFFERENT В В CHROMOSOMESCHROMOSOMES
m
m
m
m
ST
ST
2M+2ST (large and small) – Primorskiy Region (Nezhino vil.)
2M (middle and small) – Primorskiy Region (Ussuriyskiy Reserve)
M
M
MM
2n=48+4Bs
2n=48+2Bs
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SIZE AND MORPHOLOGY TYPES OF B CHROMOSOMES (Bs)
M M
ST
M
M
M
M
M
M
M M
SMM-mi
M-mi
Macro Bs: M –metacentrics, SM- submetacentic, ST-subtelocentric and
mi - mini B chromosomes, seems as metacentrics (M).
2n=48+7Bs 2n=48+7Bs
Evoron Lake
Borisovskoye plateau
1515
TYPES OF B CHROMOSOMESTYPES OF B CHROMOSOMES
0
20
40
60
80
100
120
LargeM,SM,ST
MiddleM,SM,ST
SmallM,SM,ST
mini Small A micro
Types of B chromosomes
Porti
on o
f soe
cim
ens,
%
Magadan Reg.Amur Reg.Jewish Reg.Khabarovsk Reg.Primorsky Reg.
n=23(6,5%)
n=5(1,4%)n=24 (6,8%) n=33 (9,3%)
n=164(46,2%)
n=264(74,4 %)
Large M,SM,ST Middle M,SM,STSmall M,SM,ST miniSmall A micro
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THE B CHROMOSOME THE B CHROMOSOME SYSTEMSYSTEM
• There There 78 variants78 variants of the B chromosome system of the B chromosome system have been first found out, distinguished by the have been first found out, distinguished by the number, size and morphology of B-chromosomes. number, size and morphology of B-chromosomes.
• We described 22 variants in animals with stable We described 22 variants in animals with stable karyotype (n = 136). The greatest variety of the karyotype (n = 136). The greatest variety of the variants (up 76) has been found in mosaics variants (up 76) has been found in mosaics divided into two subgroups - with one and with divided into two subgroups - with one and with two or more prevailing variants. In the first two or more prevailing variants. In the first subgroup (n = 90) 68 and in another subgroup (n subgroup (n = 90) 68 and in another subgroup (n = 129) - 104 combinations of the variants have = 129) - 104 combinations of the variants have been revealed. been revealed.
• The combinations of the variants and their The combinations of the variants and their percent correlations percent correlations were often uniquewere often unique. .
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DISTRIBUTIONDISTRIBUTION OF DEFINITE OF DEFINITE VARIANTS OF THE B CHROMOSOME VARIANTS OF THE B CHROMOSOME SYSTEMSYSTEM
Stable, n=136
38(28%) 43
(31%)
22(16%)8 (6%)
16(12%)
9(7%)
B=0B=1M,smallB=1M,middleB=2M,smallB=1M,middle+1M,smallother
Mosaics, n=219
76(35%)
33(15%)
44 (20%)
20(9%)
31 (14%)15 (7%)
B=0B=1M,smallB=1M,middleB=2M,smallB=1M,middle+1M,smallothera b
As rule, sector “Other” includes unique variants of the B chromosome system
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THE OCCURRENCE VARIANTS OF THE OCCURRENCE VARIANTS OF THE B CHROMOSOME SYSTEMTHE B CHROMOSOME SYSTEM
• The optimum chromosome number (50) has been The optimum chromosome number (50) has been established as in animals with stable karyotype (a) established as in animals with stable karyotype (a) and in mosaics (b)and in mosaics (b)
• Variants = size and morphology variants.Variants = size and morphology variants.
0
1
2
34
5
6
7
48 49 50 51 52Chromosome number
Nu
mb
er
of
va
ria
nts
0
5
10
1520
25
30
35
Po
rtio
n o
f a
nim
als
, %
Number of variantsPortion of animals
0
5
10
15
20
25
48 49 50 51 52 53 54 55Chromosome number
Num
ber o
f var
iant
s
0
5
10
15
20
25
30
35
Por
tion
of a
nim
als,
%
Number of variants Portion of animals
a b
MosaicsStable
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CONCLUSIONS:CONCLUSIONS:
• The predominance of mosaics have been The predominance of mosaics have been revealed in populations of the Russian Far revealed in populations of the Russian Far East. East.
• The percentage of mosaics are various The percentage of mosaics are various both in both in the different populations and between the the different populations and between the samples from one population, but practically samples from one population, but practically no differences in the united populations of no differences in the united populations of three geographic regions.three geographic regions.
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CONCLUSIONS:CONCLUSIONS:• The spectra of B chromosome variability The spectra of B chromosome variability
were wider in mosaics (from 0 to 7) in were wider in mosaics (from 0 to 7) in comparison with animals with stable comparison with animals with stable karyotype (from 0 to 4).karyotype (from 0 to 4).
• The optimum chromosome number (50) The optimum chromosome number (50) has been established in mosaics as well in has been established in mosaics as well in animals with stable karyotype.animals with stable karyotype.
2121
CONCLUSIONS:CONCLUSIONS:
• The adaptive role of the low number of B The adaptive role of the low number of B chromosomes (1-2) is assumed and the B chromosomes (1-2) is assumed and the B chromosome system seems not to be chromosome system seems not to be balanced in the species in whole. balanced in the species in whole.
• The distribution of mice with the similar The distribution of mice with the similar variants of the B chromosome system in variants of the B chromosome system in the Far-Eastern populations of species the Far-Eastern populations of species seems to be of the chaotic nature.seems to be of the chaotic nature.
2222
2323
THE OCCURRENCE OF MOSAICS THE OCCURRENCE OF MOSAICS
Khabarovsk Region, n=67
22,4
16,4
61,2
without Bs stable,with Bs mosaics
Magadan, Jewish and Amur Regions, n=20
030
70
without Bs stable,with Bs mosaics
Primorsky Region, n=268
10,4
28,4
61,2
without Bs stable,with Bs mosaics
The Russian Far East, total n=355
12,1
26,261,7
without Bs stable,with Bs mosaics
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B-CHROMOSOME B-CHROMOSOME NUMBERSNUMBERS in mosaicsin mosaics
0
10
20
30
40
50
0В 1В 2В 3В 4В 5В 6В 7В
number of B-chromosomes
num
ber
of a
nim
als,
%
Magadan, Amur, Jewish & Khabarovsk Reg.Primorskiy Reg.
2525
NUMBER OF CELLULAR NUMBER OF CELLULAR CLONESCLONES
0
5
10
15
20
25
30
35
40
nu
mb
er o
f sp
ecim
ens,
%1 2 3 4 5
number of cellular clones
Magadan, Amur & Jewish Reg.
Khabarovsk Reg.
Primorsky Reg.
Mosaics were differed by number of cellular clones and their ratios. As a whole, number of clones was varied from 2 to 5 in mosaics from different localities. For example, from Amur and Jewish Regions near 40% animals had as prevailed three cellular clones and 30% had one clone (or stable karyotype). And from Khabarovsk and Primorsky Regions near 30% were specimens with two clones and near 40% ones had stable karyotypes.