1. THE KOREAN FIELD MOUSE APODEMUS PENINSULAE (RODENTIA) AS A MODEL STUDY OF B CHROMOSOME POLYMORPHISM IN MAMMALIA Galina V. Roslik, Irina V. Kartavtseva Institute of Biology & Soil Science, FEB RAS, Vladivostok, (Russia)

2. Supernumerary (or Additional, or B) chromosomes – are enigmatic part of the eukariotic genome. The problem of B chromosome polymorphism is very important for understanding the existence and role of the "extra" DNA in the Mammalia. B chromosome polymorphism is widely distributed in plants and rarely in animals. (Vujošević, Blagojević, 2004) or – 70 (Трифонов и др., 2010)B chromosomes have near 50 (Vujošević, Blagojević, 2004) or – 70 (Трифонов и др., 2010) species of Mammals..

3. The standard chromosome set of the Korean field mouse, Apodemus peninsulae contains 48 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 chromosome morphotypes are different in size (vary from big to small) and morphology (vary from macro to micro Bs, more frequently meta-, submetacentrics and micro Bs and rare subtelo-, acrocentrics and mini Bs).

4. THE AIM OF THE WORK WAS: To analyse B chromosome polymorphism of the Korean field mouse Apodemus peninsulae Thomas 1906 using different cytogenetic methods and approaches

5. Routine methods: - the total number of chromosomes and identify as A and B chromosomes - the diversity of their size and morphology (morphotype) of B chromosomes - the nature of mosaicism (cellular clones)

6. KARYOTYPE OF Apodemus peninsulae (A) AND B CHROMOSOME MORPHOTYPES : B – 1-6 GROUPS, C – SCHEME X V X V x v x(,)v(,).. M/SM,ST M/SM,ST M,SM ST/A mini (M/A) micro A B C

7. B CHROMOSOME MORPHOTYPES IN A. PENINSULAE 2n=48+3B Giemsa staining 2n=48+7B Acetoorcein staining Numbers – groups of B chromosome morphotypes 2 2 3 1 1 2 2 3 3 4 Primorskii RegionKhabarovsk Region

8. DISTRIBUTION OF B CHROMOSOME MORPHOTYPES IN THE FAR EAST A – animals with slable karyotype; B – mosaics (summarized data), C - one locality – Ussuriiskii Reserve. Arabic numerals – number of specimens Scheme of B chromosome morphotypes are given in the legend A C B  The combinations of the clones were often unique in mosaics. aAaA C

9. AREA AND DISTRIBUTION OF B CHROMOSOME MORPHOTYPES IN A. PENINSULAE - our data, 41 clons – Transbaikalia, Chita, Tuva Regions (Roslik, Kartavtseva, 2003) and 78 individual clones – The Far East of Russia Roslik, Kartavtseva, 2012) - literature data, 192 clones – Siberia (Borisov,1990; 2008; 2010; Borisov, Bochkarev, 2008)

10. DIFFERENTIAL METHODS: the autosomic pairs, sex chromosomes, the peculiarities and patterns of structural organization of A and B chromosomes

11. DIFFERENTIAL STAINING OF A. PENINSULAE CHROMOSOMES: a – С – banding, В = 14, West Siberia, b – G – banding, В = 3,Primorkii Reg., c – Q – banding, В = 5, Khabarovskii Reg. Arrows arrowheads Arrows – macro B chromosomes, arrowheads – micro B chromosomes. a, b – Kartavtseva, Roslik, 2004; c – Roslik, 2006. a б b c

12. SHEME OF DIFFERENTIAL PATTERNS OF В CHROMOSOMES а – С - banding, b – G – banding (after: Borisov, 1981 and Borbiev, 1991) a b 17 18 19 10 11 12 13 14 IN THE FAR EAST OF RUSSIA: a) only types №№ 5 or 8; b) types №№ 5, 7, 11, 13 or new № 15 – Novolitovsk, Primorskii Reg. (Kartavtseva et al., 2000). 15 SIBERIA

13. Ag-NOR – STAINING OF CHROMOSOMES IN A. peninsulae Arrows are Ag-NOR – active regions in В chromosomes, arrowheads – Ag-NOR activity in the telomeric regions of aytosomes (2 pairs) (from: Rubtsov et al., 2004). ? Their possible transcriptional activity remains an open question.? Their possible transcriptional activity remains an open question.

14. TWO-COLOR FISH OF A. PENINSULAE METAPHSE CHROMOSOMES WITH DNA PROBES a, b – siberian mice, c – far-eastern mice. Green – probes, derived from macro Bs, Red – probes from centromeric C-positive regions of aytosomes, Blue - DAPI –staining (Rubtsov et al., 2004; 2005). X, Y – sex chromosomes, M – macro Bs, m – micro Bs. c M M Different possible pathways for B chromosome origin in siberian and far-eastern mice: either from autosomes or sex chromosomes (Rubtsov et al., 2004; 2005; 2009).

15. CONCLUSIONS: The significance of cytogenetic methods for the comprehensive study on B chromosome polymorphism in Apodemus peninsulae have been shown. The significance of cytogenetic methods for the comprehensive study on B chromosome polymorphism in Apodemus peninsulae have been shown. So, each method makes a several contribution to the analysis of mice karyotypes, making in whole, an integrated picture of the B chromosome study. So, each method makes a several contribution to the analysis of mice karyotypes, making in whole, an integrated picture of the B chromosome study. Thus, it appears that altogether cytogenetic methods and approaches (routine and differential) were very relevant in the study of B chromosome polymorphism in Mammalia. Thus, it appears that altogether cytogenetic methods and approaches (routine and differential) were very relevant in the study of B chromosome polymorphism in Mammalia.

16. This work was partly supported by DVO grant 12-II-СО-06-018.