Cytogenetic analysis of cryptic species in allopatric population (2n = 60, NF = 82) of Nannospalax sp. (Spalacidae, Rodentia): conventional karyotype, constitutive heterochromatin, and NOR localization

doi:10.21203/rs.3.rs-6277258/v1

Download PDF

Research Article

Cytogenetic analysis of cryptic species in allopatric population (2n = 60, NF = 82) of Nannospalax sp. (Spalacidae, Rodentia): conventional karyotype, constitutive heterochromatin, and NOR localization

https://doi.org/10.21203/rs.3.rs-6277258/v1

This work is licensed under a CC BY 4.0 License

You are reading this latest preprint version

In the present study, the 2n = 60, NF = 82 chromosomal form of blind mole rats, Nannospalax sp., from Arapgir-Malatya Province in Turkey was investigated. Conventional chromosome staining, NOR (Nucleolus Organizer Region), and C-banding analysis were carried out on specimens of this population. The karyotype including 10 submetacentric pairs and 19 acrocentric pairs of autosomes and fundamental number is (NFa) 78. In all of the specimens studied the NOR’s were localized in the telomeric regions of the short arms of the 2 autosome pairs (nos. 2 and 7), and only one homologue of the pairs nos. 4 and 10 autosomes has a positive silver signal. C-heterochromatin regions were found in the centromeric region of whole bi-armed autosomal pairs. One of the X chromosomes has a pericentromeric C-positive band, whereas the other has a dot-like C-positive band.

Nannospalax

mole rat

karyotype

Malatya

Turkey

Mole rats (family Spalacidae) are the major component of steppe habitats in the Palearctic region (Topachevski 1976; Savic and Soldatovic 1977), and is the most speciation groups taxon, which is currently regarded to be composed of more than 60 chromosomal forms in 2 genera (Spalax and Nannospalax) in distributon area and the genus Nannospalax includes three morphospecies: Nannospalax leucodon, Nannospalax nehringi, and Nannospalax ehrenbergi in Turkey (Ellerman and Morrison-Scoot 1951; Topachevski 1976; Musser and Carleton 2005). Despite almost 30–40 million years of the family Spalacidae evolutionary background, speciation is still in progress and many populations are at different levels of the process (Savic and Nevo 1990; Nevo et al. 1995; Ünay 1996; Şen and Sarica 2011). The genus Nannospalax which is one of the youngest genera (about 24 million years ago) of this family (Hadid et al. 2012), shows a relatively high rate of karyotypic rearrangements and molecular divergence among mammals. These evolutionary dynamics provoke taxonomic uncertainties on the one hand but make this group a perfect model for evolutionary research on the other hand (Savic and Nevo 1990; Nevo et al. 1995; He et al. 2019). Overall, the Nannospalax mole rats abound with cryptic species (Nevo et al. 2001; Csorba et al. 2015; Savic et al. 2017; Bugarski-Stanojević at al. 2022, 2024). Cryptic species are those that cannot readily be distinguished on the basis of phenotypic variation alone (Struck et al. 2018); they have created challenges in myriad areas of the life sciences, especially in taxonomic systems. Not all “cryptic” species, however, are truly cryptic; many are simply underexplored morphologically (Nastasi et al. 2024). Cryptic species complexes where there is a large diversity of karyomorphs with autapomorphies must have originated due to plasticity in the ancestral karyomorph. The multiple karyotypic forms found in cryptic species could constitute, therefore, important examples of non-adaptive or adaptive chromosomal radiation, depending on the relation of the character with the environment (Kavalco and Pasa 2023).

Chromosomal studies have often significantly contributed to understanding of the phylogeny and systematics of small mammals owing to extensive karyotypic variation recorded in their populations (Zima 2000; Arslan et al. 2011a). Changes in C-heterochromatin amount and distribution are among important mechanisms producing this variation. C- and Ag-NOR banding techniques are frequently used in animals and thus are useful for examining intra- and interspecific chromosomal differences between closely related species (Arslan et al. 2011a; Zhu et al. 2019). The structure, number, and morphology of the nucleolar organizer region may be specific to populations, species, and subspecies. Nucleolus Organizer Regions (NORs) are frequently used as markers to show intra- and inter-species chromosomal polymorphism in animals. Species with limited gene exchange owing to geographic isolation have high NORs and chromosomal diversity. Therefore, even in small but isolated populations of these species, different karyotypes are found. The homogeneity of this character and the degree of diversity within a taxon largely determines the use of NORs in explaining relationships (Yüksel and Gaffaroğlu 2008).

Conventional karyological studies carried out in Malatya province: Yüksel (1984) 2n = 60, NF = 80 from Yazıhan; Gülkaç and Yüksel (1989) 2n = 60, NF = 80 from Akçadağ and NF = 82 from Arguvan; Nevo et al. (1995) 2n = 60, NF = 78 from 30 km west of Malatya; Ivanitskaya et al. (1997) 2n = 60, NF = 78 from 12 km east of Malatya; Ulutürk et al. (2009) 2n = 60, NF = 82 from Arguvan, Hekimhan, and Arapgir; Coşkun et al. (2010) 2n = 60, NF = 78 from Doğanşehir, Kale and Akçadağ (Table 1).

So far C-, and NOR banding of different chromosomal forms of Nannospalax 2n = 60 were achieved from Turkey by various authors (Ivanitskaya et al. 1997, 2008; Gülkaç and Küçükdumlu 1999; Arslan and Bölükbaş 2010; Arslan et al. 2011b; Aşan Baydemir et al. 2013; Yağcı 2017). However, there is not any banded karyotypes of Nannospalax population (2n = 60, NF = 82) in Arapgir (Malatya) region. The aim of the present study is to describe in detail the conventional chromosome staining and the distribution of the NORs and C-heterochromatin in the karyotype of Nannospalax sp. from Arapgir (Malatya).

Cytogenetic analyses were performed on three specimens of mole rat from Arapgir, Malatya (Fig. 1). Karyotype preparations were obtained from the bone marrow of animals treated with colchicine (Ford and Hamerton 1956). After preparation of chromosome slides, air-dried preparations were stained conventionally with Giemsa. Constitutive heterochromatin and nucleolus organizer regions were detected in individual autosomal and sex chromosome pairs via C-banding (Sumner, 1972), and Ag-NOR staining (Howell and Black 1980). From each specimen slides were prepared, and well-spread metaphase plates were analysed. The results were compared with previously published accounts on 2n = 60 chromosomal forms carried out in Turkey. Standard voucher specimens (skins and skulls) are deposited in the Department of Biology, Faculty of Science, Dicle University, Diyarbakır, and Batman University Science and Art Faculty, Biology Department, Turkey.

Conventional karyotype

All karyotyped mole rats from the population of Arapgir had identical karyotypes with 2n = 60, NF = 82 and NFa = 78. The autosomal set consisted of ten pairs submetacentric (chromosome nos. 1–10) and 19 pairs large-to-small acrocentric pairs (chromosome nos.11–29) of gradually decreasing size). The X chromosome was the second large submetacentric, and the Y chromosome was dot-sized acrocentric (Fig. 2).

NOR banding patterns

NORs were found in two bi-armed autosomal pairs (pairs 2 and 7) in the complements of all the specimens, and in the telomeric region of the short arms of those pairs, and only one homologue of the pairs numbers 4 and 10 autosomes has determined a positive silver signal (Fig. 3).

C-banding

In mole rats of Arapgir, C-positive heterochromatic blocks were located in centromeric region of all biarmed autosomes (1–10) and while the one of the X chromosomes has a large pericentromeric C-positive region, the other one X chromosome has a dot like centromeric C positive (Fig. 4)

The distribution of C-heterochromatin followed the same pattern in all examined specimen sets. Some biarmed autosome pairs (numbers 1, 5, 7, and 8) exhibited distinct dark centromeric C-bands. Other biarmed autosome pairs (numbers 2, 3, 4, 6, 9, and 10) exhibited a weaker C-positive band.

The 2n = 60 chromosomal form shows the largest distribution areas among chromosomal forms of Nannospalax in Anatolia. The 2n = 60 chromosomal form in Turkey were first recorded by Yüksel (1984) from Malatya Province in the central-eastern Anatolia. Later, 2n = 60, the most common chromosomal form of mole rats in central Anatolia, had been reported by numerous authors (Gülkaç and Yüksel 1989; Nevo et al. 1995; Ivanitskaya et al. 1997; Gülkaç and Küçükdumlu 1999; Ulutürk et al. 2009; Coşkun et al. 2010, and see Table 1). The karyotype in the 2n = 60 chromosomal forms are variable and NF range of 72–84 was reported by previous authors (Matur and Sözen 2005; Kankılıç et al. 2007, 2009, 2010; Sözen et al. 2011, 2013; Arslan et al. 2016). However, the geographical continuity of the known populations is in doubt. In the Malatya province two different chromosomal forms of 2n = 60 (2n = 60a, NF = 82 and 2n = 60b, NF = 78) reported by Coşkun et al. (2010), and they claimed that these two forms seem to be separated by the Tohma Stream.

The NORs of Nannospalax populations in Malatya province were first studied by Ivanitskaya et al. (1997). According to these researchers, in all the samples, the NORs were localised in the short arms of 3 pairs of sub-telocentric chromosomes in this population. Gülkaç and Küçükdumlu (1999) determined that Nannospalax (Spalax leucodon) specimens obtained from Malatya, the karyotype consitsts of 30 chromosome pairs and the NORs were terminally located on 3 pairs of large subtelocentrics. All of the individuals displayed a consistent number of NORs per cell. NORs were not found on the sex chromosomes of Nannospalax (Spalax leucodon).

Table 1

Karyotype records of the 2n = 60 chromosomal forms of *Nannospalax* from Turkey. NF – fundamental number of chromosomal arms (See Fig. 1 for location of the sites).
2n	NF	m/sm/st	a	X	Y	C band	NOR	Locality		Reference
2n = 60	80	18	40	sm	st	--	--	Malatya	Yazıhan	Yüksel 1984
	80	18	40	sm	st	--	--	Malatya	Akçadağ	Gülkaç and Yüksel 1989
	82	20	38	sm	a	--	--	Malatya	Arguvan	Gülkaç and Yüksel 1989
	78	16	42	sm	a	--	--	Malatya	30 km W	Nevo at al. 1995
	78	16	42	--	--	14 m/sm + 8a + XY	6 m/sm	Malatya	12 km E	Ivanitskaya et al. 1997
	--	--	--	--	--	--	6 m/sm	Malatya		Gülkaç and Küçükdumlu 1999
	78	16	42	Sm	a	16 + XY	8 m/sm (W)	Çankırı,	Orta, Sanabozu	Ivanitskaya et al. 2008
	78	16	42	Sm	a	16 + XY	9 m/sm (R)	Bursa	İnegöl	Ivanitskaya et al. 2008
	82	20	38	M	a	--	--	Malatya	Arguvan, Hekimhan, Arapgir	Ulutürk et al. 2009
				Sm	a	--	--	Elazığ,	Keban (Denizli)	Coşkun et al. 2010
								Erzincan,	Çitköy, Dutluca
								Sivas	Divriği
	78	16	42	sm	a	--	--	Elazığ,	Keban (Çirkan)
	78	16	42	sm	a	--	--	Malatya	Doğanşehir, Kale, Akçadağ
	76	14	44	sm		14 m/sm + XY	8 m/sm	Aksaray	Gülağaç, Ortaköy, Ağaçören	Arslan and Bölükbaş 2010
	78	16	42	sm	m	16 m/sm + XY	8 m/sm	Aksaray	Güzelyurt, Sarıyahşi, Merkez	Arslan and Bölükbaş 2010
	74	12	46	Sm	st	12 m/sm + XY	8 m/sm	Konya	Hadim, Karatay	Arslan et al. 2011b
	78	16	42	--	--	16m/sm + XY + 10a	8 m/sm		Ilgın, Höyük, Sarayönü
	79	17	21–	Sm	st	17 + XY + 12a	8 m/sm		Bozkır, Çumra, Selçuklu, Güneysınır, Meram
	80	18	40	Sm	St	18 + XY	8 m/sm		Cihanbeyli
	80	18	40	Sm	a	--	8 m/sm	Konya	Cihanbeyli, Kulu	Aşan Baydemir et al. 2013
	--	--	--	--	--	18 m/sm + XY	6 m/sm	Bilecik	Söğüt, Pazaryeri	Yağcı 2017
	82	20	38	Sm	a	20 m/sm + XX	6 m/sm	Malatya	Arapgir	This study

Nevo et al. (1995)d lkaç and Küçükdumlu (1999) reported that the NORs on homologue chromosomes do not exhibit heteromorphism in Nannospalax (Spalax leucodon). The number of NORs carrying chromosomes and the location of the NORs on the chromosomes usually show remarkable variation among species. Sözen et al. (2006) reported that it appears that changes in NORs have occurred in strict association with differentiation and evolution of species. Ivanitskaya et al. (2008) reported that both 2n = 60R and 2n = 60W chromosomal forms have NORs localized in the five pairs of sub-telocentric autosomes. Arslan et al. (2011b) reported the NORs have in 4 pair autosomes of the four chromosomal forms (NF = 74, 78, 79 and 80) of 2n = 60 from Konya

Distributions of NORs patterns were very similar to those in Malatya (Ivanitskaya et al. 1997; Gülkaç and Küçükdumlu 1999) and Bilecik (Yağcı 2017), but some differences in Bursa, Çankırı (Ivanitskaya et al. 2008), Aksaray (Arslan and Bölükbaş 2010), Konya (Arslan et al. 2011b).

Nannospalax (S. leucodon) samples (2n = 60, NF = 78) from Malatya, all subtelocentric chromosomes possess completely heterochromatic short arms, with the exception of the pair 7; among the acrocentric chromosomes only four pair; have pericentromeric blocks of heterochromatin; in the submetacentric X-chromosomes the pericentromeric blocks of heterochromatin are not as dark as in the autosomes (Ivanitskaya et al. 1997). Chromosomes of blind mole rats from Malatya (2n = 60, NF = 78, NFa = 74) given by Ivanitskaya et al. 1997 differed distinctly with the C-banding pattern of Arapgir population (2n = 60, NF = 82, NFa = 78).

In terms of biarmed chromosomes, C-heterochromatin distributions were very similar those in Çankırı and Bursa (Ivanitskaya et al. 2008), Aksaray (Arslan and Bölükbaş 2010) and Konya (Arslan et al. 2011b), but some differences in Malatya (Ivanitskaya et al. 1997). According to the acrocentric chromosomes C-heterochromatin distributions differ from in Malatya (Ivanitskaya et al. 1997) and Konya (Ilgın, Höyük, Sarayönü, Bozkır, Çumra, Selçuklu, Güneysınır and Meram) (Arslan et al. 2011b). All sex chromosomes possesses C-heterochromatin blocks in all 2n = 60 populations in Anatolia (See Table 1). Nucleolus organizer regions and C-heterochromatin distributions have been detected for the first time in this study for Nannospalax sp. 2n = 60, NF = 82 chromosomal form of Turkey.

To date, no detailed cytogenetic investigations have been performed on representatives of Nannospalax sp. which inhabit a small territory in the northern part of the Tohma River basin in Arapgir (Malatya). Coşkun et al (2010) stated that the two cryptic species (2n = 60a, NF = 82 and 2n = 60b, NF = 78) of mole rats have distributed in Malatya province and they argued the Tohma River acts as a barrier between two cryptic chromosomal forms. In this study, the presence of chromosomal forms 2n = 60a, NF = 82 (Nannospalax sp.) was confirmed. Morphological examination of specimens from both chromosomal forms is necessary to reveal morphological differences and, at last to a formal species description on this cryptic species. Our study demonstrates the uncovering hidden biodiversity. We, therefore, classified these mole rats as Nannospalax sp. but increasing the sample size is needed to rule out of this cryptic species.

Funding

The authors declare that no funds, grants, or other support was received during the preparation of this manuscript.

Conflict of interest The authors declare no conflict of interest.

Ethical approval No ethical approval is required, not applicable.

Author contribution

All authors made equal contributions to this study.

Data availability

All data supporting the findings of this study are available within the paper.

Arslan A, Bölükbaş F (2010) C-heterochromatin and NORs distrubution of mole rat, Nannospalax xanthodon from Aksaray. Turk Caryologia 63:398404. https://doi.org/10.1080/00087114.2010.10589752
Arslan A, Toyran K, Gözütok S, Yorulmaz T (2011a) C- and NOR stained karyotypes of mole rat, Nannospalax xanthodon (2n = 54) from Kırıkkale. Turk Turk J Biol 35:655–661. https://doi.org/10.3906/biy-1011-2
Arslan A, Akan Ş, Zima J (2011b) Variation in C-heterochromatin and NOR distribution among chromosomal races of mole rats (Spalacidae) from Central Anatolia. Turk Mamm Biol 76:28–35. https://doi.org/10.1016/j.mambio.2010.01.005
Arslan A, Krystufek B, Matur F, Zima J (2016) Review of chromosome races in blind mole rats (Spalax and Nannospalax). Folia Zool 65:249301. https://doi.org/10.25225/fozo.v65.i4.a1.2016
Aşan Baydemir N, Yağcı T, Çakır Ş (2013) Karyological studies of the 2n = 60 cytotype of Nannospalax nehringi from Central Anatolia. Caryologia 66:49–53. https://doi.org/10.1080/00087114.2013.780441
Bugarski-Stanojević V, Stamenković G, Jojić V, Ćosić N, Ćirović D, Stojković O, Veličković J, Savić I (2022) Cryptic diversity of the European blind mole rat Nannospalax leucodon species complex: Implications for conservation. Animals 12:1097. https://doi.org/10.3390/ani12091097
Bugarski-Stanojević V, Dokić M, Stamenković G, Barišić Klisarić N, Stojković O, Jojić V, Savić I (2024) A cryptic subterranean mammal species, the lesser blind mole rat (Nannospalax leucodon syrmiensis) –Retreated but not extinct. Animals 14:774. https://doi.org/10.3390/ani14050774
Coşkun Y, Ulutürk S, Kaya A (2010) Karyotypes of Nannospalax (Palmer 1903) populations (Rodentia: Spalacidae) from central-eastern Anatolia, Turkey. Hystrix It J Mamm 21:89–96. https://doi.org/10.4404/hystrix-21.1-4487
Csorba G, Krivek G, Sendula T, Homonnay ZG, Hegyeli Z, Sugár S, Farkas J, Stojnić N, Németh A (2015) How can scientific researches change conservation priorities? A review of decadelong research on blind mole-rats (Rodentia: Spalacinae) in the Carpathian Basin. Therya 6:103–121. https://doi.org/10.12933/therya-15-245
Ellerman JR, Morrison-Scott TCS (1951) Checklist of Palaearctic and Indian Mammals 1758 to 1946. British Museum (Natural History), London
Ford CE, Hamerton JL (1956) A colchicine, hypotonic citrate, squash sequence for mammalian chromosomes. Stain Technol 31:247–251. https://doi.org/10.3109/10520295609113814
Gülkaç MD, Yüksel E (1989) A cytogenetical study on blind mole rats around Malatya province. Doğa. Turk J Biol 13:63–71
Gülkaç MD, Küçükdumlu İ (1999) Variation in the nucleolus organizer regions (NORs) in two mole rat species (Spalax leucodon and Spalax ehrenbergi). Turk J Biol 23:153–158
Hadid Y, Németh A, Snir S, Pavlícek T, Csorba G, Kázmér M, Major A, Mezhzherin S, Rusin M, Coşkun Y, Nevo E (2012) Is evolution of blind mole rats determined by climate oscillations? PLoS ONE 7:e30043. https://doi.org/10.1371/journal.pone.0030043
He Y, Hu S, Ge D, Yang Q, Connor T, Zhou C (2019) Evolutionary history of Spalacidae inferred from fossil occurrences and molecular phylogeny. Mam Rev 50:11–24. https://doi.org/10.1111/mam.12170
Howell WM, Black DA (1980) Controlled silver staining of nucleolar organizer regions with a protective colloidal developer: a 1-step method. Experientia 36:1014–1015. https://doi.org/10.1007/BF01953855
Ivanitskaya E, Coşkun Y, Nevo E (1997) Banded karyotypes of mole rats (Spalax, Spalacidae, Rodentia) from Turkey. J Zool Syst Evol Res 35:171–177. https://doi.org/10.1111/j.1439-0469.1997.tb00421.x
Ivanitskaya E, Sözen M, Rashkovetsky L, Matur F, Nevo E (2008) Discrimination of 2n = 60 Spalax leucodon cytotypes (Spalacidae, Rodentia) in Turkey by means of classical and molecular cytogenetic techniques. Cytogenet Genome Res 122:139e149. https://doi.org/10.1159/000163091
Kankılıç T, Kankılıç T, Çolak R, Çolak E, Karataş A (2007) Karyological comparison of populations of the Spalax leucodon Nordmann, 1840 superspecies (Rodentia: Spalacidae) in Turkey. Zool Middle Eastvol 42:15–24. https://doi.org/10.1080/09397140.2007.10638242
Kankılıç T, Çolak E, Kankılıç T (2009) Macroanatomical and karyological features of two blind mole rat subspecies (Rodentia: Spalacidae) from Turkey, Anat. Histol Embryol 38:145–153. https://doi.org/10.1111/j.1439-0264.2008.00913.x
Kankılıç T, Kankılıç T, Seker PS, Çolak R, Selvi E, Çolak E (2010) Contributions to the karyology and distribution areas of cytotypes of Nannospalax leucodon (Rodentia: Spalacidae) in Western Anatolia. Acta Zool Bulg 62:161–167
Kavalco KF, Pasa R (2023) Chromosomal radiation: A model to explain karyotypic diversity in cryptic species. Genet Mol Biology 46 1. https://doi.org/10.1590/1678-4685-GMB-2023-0116
Matur F, Sözen M (2005) A karyological study on subterrranean mole rats of the Spalax leucodon Nordmann, 1840 (Mammalia: Rodentia) superspecies in Northwestern Turkey, Zool. Middle East 36:5–10. https://doi.org/10.1080/09397140.2005.10638121
Musser GG, Carleton MD (2005) Order Rodentia. In: Wilson DE, Reeder DM (eds) Mammal Species of the World: A Taxonomic and Geographic Reference. Johns Hopkins University, Baltimore, MD, USA, pp 745–1601
Nastasi LF, Tooker JF, Davis CK, Smith CN, Frey TS, Hatfield MJ, Presnall TM, Hines HM, Deans AR (2024) Cryptic or underworked? Taxonomic revision of the Antistrophus rufus species complex (Cynipoidea,Aulacideini). J Hymenoptera Res 97:399–439. https://doi.org/10.3897/jhr.97.121918
Nevo E, Filippucci MG, Redi C, Simson S, Heth G, Beiles A (1995) Karyotype and genetic evolution in speciation of subterranean mole rats of the genus Spalax in Turkey. Biol J Linn Soc 54:203–229. https://doi.org/10.1016/0024-4066(95)90018-7
Nevo E, Ivanitskaya E, Beiles A (2001) Adaptive radiation of blind subterranean mole rats: naming and revisiting the four sibling species of the Spalax ehrenbergi superspecies in Israel: Spalax galili (2n = 52), S. golani (2n = 54), S. carmeli (2n = 58) and S. judaei (2n = 60). Bachkhuys Publisher, Leiden (The Netherlands), p. 202
Savić I, Ćirović D, Bugarski-Stanojević V (2017) Exceptional Chromosomal Evolution and Cryptic Speciation of Blind Mole Rats Nannospalax leucodon (Spalacinae, Rodentia) from South-Eastern Europe. Genes 8:292. https://doi.org/10.3390/genes8110292
Savic I, Nevo E (1990) The Spalacidae: Evolutionary history, speciation and population biology. [In: Evolution of subterranean mammals at the organismal and molecular levels. In: Nevo E. and Reig O. A., (Eds.) New York, 129–153
Savic I, Soldatovic B (1977) Contribution to the study of ecogeographic distribution and evolution of chromosomal forms of the Spalacidae from the Balkan Peninsula. Arch Biol Sci 29:141–156 (In Serbian with English Summary)
Sözen M, Çataklı K, Eroğlu F, Matur F, Sevindik M (2011) Distribution of chromosomal forms of Nannospalax nehringi (Satunin, 1898) (Rodentia: Spalacidae) in Çankırı and Çorum. Provinces Turk 35:367–374 Turk. J. Zool. https://doi.org/10.3906/zoo-0905-3
Sözen M, Matur F, Çolak E, Özkurt Ş, Karataş A (2006) Some karyological records and a new chromosomal form for Spalax (Mammalia: Rodentia) in Turkey. Folia Zool 55:247–256
Sözen M, Çolak F, Sevindik M, Matur F (2013) Cytotypes of Nannospalax xanthodon (Satunin, 1898) (Rodentia, Spalacidae) from western Anatolia. Turk J Zool 37:462–469
Struck TH, Feder JL, Bendiksby M, Birkeland S, Cerca J, Gusarov VI, Kistenich S, Larsson KH, Liow LH, Nowak MD, Stedje B, Bachmann L, Dimitrov D (2018) Finding evolutionary processes hidden in cryptic species. Trends Ecol Evol 33:153–163. https://doi.org/10.1016/j.tree.2017.11.007
Sumner AT (1972) A simple technique for demonstrating centromeric heterochromatin. Exp Cell Res 75:304–306. https://doi.org/10.1016/0014-4827(72)90558-7
Şen S, Sarıca N (2011) Middle-Late Miocene Spalacidae (Mammalia) from western Anatolia, and the phylogeny of the family. Yerbilimleri 32:21–50
Topachevskii VA (1976) Fauna of the USSR: mammals: Mole rats, Spalacidae. American Publishing Company, New Delhi. https://doi.org/10.5962/bhl.title.46318
Ulutürk S, Coşkun Y, Arıkan H (2009) A Comparative karyological and serological study on two populations of Nannospalax nehringi (Satunin 1898) from Turkey. North-Western J Zool 5:349–356
Ünay E (1996) On fossil Spalacidae (Rodentia). In: Bernor RL, Fahlbusch V, Mittmann HW (eds) The evolution of Western Eurasian Neogene Mammal Faunas. Columbia University, New York, pp 246–252
Yağcı T (2017) C- and NOR-banding karyotype analysis of Nannospalax xanthodon (2n = 52, 2n = 60) and new locality for 2n = 52 cytotype from western Anatolia. Caryologia 71:7–12. https://doi.org/10.1080/00087114.2017.1396805
Yüksel E (1984) Cytogenetic study in Spalax (Rodentia: Spalacidae) from Turkey. Communications, Serie C: Biologie. 2, 1–12
Yüksel E, Gaffaroğlu M (2008) NOR phenotype of Cyprinion macrostomus (Osteichthyes, Cyprinidae). J Fisheries Sci 2:114–117
Zhu JJ, Qi H, Cai LR, Wen XH, Zeng W, Tang GD, Luo Y, Meng R, Mao XQ, Zhang SQ (2019) C-banding and AgNOR-staining were still effective complementary methods to indentify chromosomal heteromorphisms and some structural abnormalities in prenatal diagnosis. Mol Cytogenet 12:41. https://doi.org/10.1186/s13039-019-0453-1
Zima J (2000) Chromosomal evolution in small mammals (Insectivora, Chiroptera, Rodentia). Hystrix It J Mamm 11:5–15. https://doi.org/10.4404/hystrix-11.2-4143

Download PDF

Editorial decision: Major revisions
26 Jul, 2025
Reviewers agreed at journal
24 Jun, 2025
Reviewers invited by journal
24 Jun, 2025
Editor invited by journal
08 Jun, 2025
Editor assigned by journal
25 Mar, 2025
First submitted to journal
21 Mar, 2025

You are reading this latest preprint version

Cytogenetic analysis of cryptic species in allopatric population (2n = 60, NF = 82) of Nannospalax sp. (Spalacidae, Rodentia): conventional karyotype, constitutive heterochromatin, and NOR localization

Status:

Version 1

Abstract

Figures

Introduction

Material and methods

Results

Conventional karyotype

NOR banding patterns

C-banding

Discussion

Declarations

Funding

Author contribution

Data availability

References

Status:

Version 1