Punjab University Journal of Zoology 36(1): 71-79 (2021) https://dx.doi.org/10.17582/journal.pujz/2021.36.1.71.79 Research Article Karyotype Symmetry/ Asymmetry and Karyotypic Relationships of Cervidae (Artiodactyla) Taxa Halil Erhan Eroğlu Department of Biology, Faculty of Science and Art, Yozgat Bozok University, Yozgat, Turkey. Article History Received: February 26, 2019 Abstract | Karyotype asymmetry is one of the most widely used approaches in cytotaxonomic Revised: May 03, 2021 studies. The symmetry/asymmetry index (S/AI) is used to determine karyotype asymmetry in Accepted: May 18, 2021 higher animals and humans. The formula designed by the number of chromosome types is Published: June 13, 2021 S/AI = (1 × M) + (2 × SM) + (3 × A) + (4 × T) / 2n. The S/AI value varies from 1.0000 (full symmetric) to 4.0000 (full asymmetric). After a detailed literature review, the chromosomal Keywords data of 36 female species and 32 male species of family Cervidae were detected, namely (i) Artiodactyla, Cervidae, Kary- karyotype formulae, (ii) symmetry/asymmetry index values (iii) karyotype types. According otype, Phylogeny, Symmetry/ asymmetry index to the chromosomal data, two phylogenetic trees were formed. The phylogenetic trees were showed karyotypic relationships among the taxa. Novelty Statement | This is the first report on karyotype asymmetry of Cervidae. Karyotypic relationships are useful to infer processes of evolution and speciation. Karyotype asymmetry is an important parameter that helps to establish phylogenetic relationships among various species. To cite this article: Eroğlu, H.E., 2021. Karyotype symmetry/ asymmetry and karyotypic relationships of cervidae (Artiodactyla) taxa. Punjab Univ. J. Zool., 36(1): 71-79. https://dx.doi.org/10.17582/journal.pujz/2021.36.1.71.79 Introduction Wild (EW) and Extinct (EX), respectively (IUCN, 2018). ervidae (Goldfuss, 1820) is placed in the order The family Cervidae is one of the most important Artiodactyla (Owen, 1848). The family consists of at members of the world’s wildlife. Therefore, many Cleast 51 wild species in 19 genera. The Cervidae are the most taxonomic and cytotaxonomic studies have been reported widespread family of extant Artiodactyla after Bovidae related cervids till now and some of them have been (ITIS, 2019). They are distributed naturally in all continents summarized. The chromosome numbers of Cervidae are except Antarctica and Australia (Gilbert et al., 2006). The generally 2n = 50–70 (Wurster and Benirschke, 1967a, number of cervids decreases with human effects as a result 1967b; Hsu and Benirschke, 1973a, 1973b; Jorge and of uncontrolled hunting, especially in Europe, Asia and Benirschke, 1977). The majority of species have 66–70 America. According to the International Union for the chromosomes (Naik et al., 1964; Wurster and Benirschke, Conservation of Nature (IUCN) Red List, the seven species 1967a, 1967b; Gustavsson and Sundt, 1968; Koulischer et are categorized as Endangered (EN). In addition, Axis al., 1972; Sokolov et al., 1978; Wang and Du, 1983; Herzog, kuhlii (bawean deer), Elaphurus davidianus (père David’s 1987). As an extreme example, Muntiacus muntjak has the deer) and Rucervus schomburgki (Schomburgk’s deer) are lowest diploid chromosome number among mammals categorized as Critically Endangered (CR), Extinct in the (female 2n = 6; male 2n = 7) (Tanomtong et al., 2005). The chromosome numbers of genus Muntiacus are extremely diverse, ranging from 6 in Muntiacus muntjak (Tanomtong Corresponding author: Halil Erhan Eroğlu et al., 2005) to the relatively high number of 46 in Muntiacus [email protected] reevesi reevesi (Wurster and Benirschke, 1967a; Chiang et June 2021 | Volume 36 | Issue 1 | Page 71 H.E. Eroğlu al., 2004) and Muntiacus reevesi micrurus (Chiang et al., 2.0 (symmetric), 2.0 < S/AI ≤ 3.0 (between symmetric and 2004). In addition, there are B chromosomes in the family asymmetric), 3.0 < S/AI < 4.0 (asymmetric) and 4.0 = S/AI Cervidae (Abril and Duarte, 2008; Resende et al., 2011; (full asymmetric). Fiorillo et al., 2013). B chromosomes, are not necessarily necessary chromosomes, are extra chromosomes that do Sample application of symmetry/asymmetry on taxa not comply with Mendelian inheritance rules. They are The karyotypes of the sample application belong commonly found in mammals (Palestis et al., 2004). to Cervidae taxa. The Cervidae includes the ruminant mammals commonly known as deer, elk, moose and Karyotype asymmetry is an important parameter caribou. After a detailed literature review, the information in karyotype studies. Many parameters have been about family Cervidae was detected namely; (i) scientific/ proposed in the calculation of karyotype asymmetry, common names and author(s), (ii) karyotype formulae which are parameters of Stebbins classification, TF (total with B-chromosomes, if any (iii) symmetry/asymmetry form percentage), AsK (karyotype asymmetry index index values (iv) karyotype types (Table 1). percentage), Syi (symmetric index), Rec (ratios of each chromosome), A1 (intrachromosomal asymmetry index), Table 1 includes the scientific/common names A2 (interchromosomal asymmetry index), DI (dispersion and author(s) of the taxa. The databases were used for index), A (asymmetry index), CVCL (coefficient of the control of scientific names, namely IUCN Red List variation of chromosome length), CVCI (coefficient of (IUCN, 2018) and the Integrated Taxonomic Information variation of centromeric index), MCA (mean centromeric System (ITIS, 2019), because sometimes scientific names asymmetry) and S/AI. All except S/AI have been proposed can be expressed with different names in different sources. for the calculation of plant karyotype asymmetries (Eroğlu The genus Rucervus is an important example. The names et al., 2013; Peruzzi and Eroğlu, 2013; Eroğlu, 2015). The of genus are Cervus (Chandra et al., 1967; Chavananikul S/AI is used to determine karyotype asymmetry in higher et al., 1995; Thevenon et al., 2000; Bonnet-Garnier et al., animals and humans (Eroğlu, 2015). All methods use 2003) and Rucervus (IUCN, 2018; ITIS, 2019). basic measurement data such as long and short arms of chromosomes. The symmetrical karyotype is characterized In addition, Table 1 includes the symmetry/ asymmetry by chromosomes with central centromere that do not index values and the karyotype types. Calculation of these differ much between long and short arm lengths. On values is given below with Cervus albirostris karyotype. In the contrary, the asymmetric karyotype is characterized Table 1, the karyotype formulae are 2n = 66 = 2M + 2SM by chromosomes with very different long and short + 62A in female and 2n = 66 = 2M + 3SM + 61A in male. arm lengths and without a central centromere (Peruzzi and Eroğlu, 2013). The aim of this study is to reveal the S/AI (female)= (1×M)+(2 × SM) + (3 × A) + (4 × T) / 2n karyotypic relationships of Cervidae taxa by determining S/AI (female) = (1 × 2) + (2 × 2) + (3 × 62) / 66 the karyotype asymmetries. S/AI (female) = 2.9091 2.0 < S/AI (female)≤ 3.0 (between symmetric and asymmetric) Materials and Methods S/AI (male)= (1 × M) + (2 × SM) + (3 × A) + (4 × T) / 2n S/AI (male) = (1 × 2) + (2 × 3) + (3 × 61) / 66 S/A (male) = 2.8939 The karyotype symmetry/asymmetry index I 2.0 < S/A (male) ≤ 3.0 (between symmetric and asymmetric) Eroğlu (2015) reported a formula to calculate I karyotype symmetry/asymmetry index with two important The phylogenetic trees formed by chromosomal data matters. Firstly, while other parameters use chromosome in Table 1 present the karyotype relationships among the arm lengths, the S/AI parameter uses the karyotype taxa of Cervidae (Figures 1 and 2). The Figures 1 and formula. Secondly, the chromosomal lengths may contain 2 include 36 female taxa and 32 male taxa, respectively. small differences in different karyotype studies of the For two reasons, four taxa are not included in the male same species. The differences do not affect the karyotype phylogenetic tree: (i) The male subjects were not studied formula and S/A value. The S/A formula is shown below. I I in Capreolus pygargus, Mazama gouazoubira and Ozotoceros bezoarticus; only female reports (Sokolov et al., 1978; S/A = (1 × M) + (2 × SM) + (3 × A or ST) + (4 × T) / 2n I Spotorno et al., 1987; Resende et al., 2011). (ii) In the karyotype study of Hippocamelus bisulcus, there are small The formula was designed according to the number Y chromosomes that cannot be examined. Therefore, of chromosome types, namely the chromosome number chromosome cannot be classified (Spotorno et al., 1987). of metacentric (M), submetacentric (SM), acrocentric Finally, drawings of some species were added to the figures (A), subtelocentric (ST) and telocentric (T). In addition, to further clarify the karyotype relationships among taxa. a classification model was given according to the S/AI value, namely 1.0 = S/AI (full symmetric), 1.0 < S/AI ≤ June 2021 | Volume 36 | Issue 1 | Page 72 Karyotype Asymmetry of Cervidae Table 1: The karyotype formulae, index values and karyotype types of the taxa. No Family/ Species Sample 2n Autosomes and References S/AI Kary- Scientific name/common name number sex chromosomes otype type 1 Hydropotes inermis (Swinhoe, 1870) 1 F 70 68A Hsu and Benirschke, 1973b 3.0000 (F) BSA (Water deer) 1 M X = A, Y = A 3.0000 (M) 2 Muntiacus reevesi reevesi (Ogilby, 1 F 46 44A Wurster and Benirschke, 3.0000 (F) BSA 1839) (Chinese muntjac) 1 M X = A, Y = SM 1967a; Chiang et al., 2004 2.9783 (M) 3 Muntiacus reevesi micrurus (Sclater, 1 F 46 44A Chiang et al., 2004 3.0000 (F) BSA 1875) (Formosan muntjac) 1 M X = A, Y = SM 2.9783 (M) 4 Muntiacus feae (Thomas & Doria, 4 F 14 13A Tanomtong et al., 2005 3.0000 (F) BSA 1889) (Fea's muntjac) 2 M X*, Y = SM 2.8571 (M) 5 Muntiacus muntjak (Zimmermann, 3 F 6 (F) 2M + 4A Tanomtong et al., 2005 2.3333 (F) BSA 1780), (Indian muntjac) 2 M 7 (M) X**, Y = M 2.2857 (M) 6 Capreolus capreolus (Linnaeus, 1758) 1 F 70 68A Wurster and Benirschke, 2.9714 (F) BSA (European roe deer) 1 M X = SM, Y = ST 1967b 2.9857 (M) 7 Capreolus pygargus (Pallas, 1771) — 70 68A Sokolov et al., 1978 2.9714 (F) BSA (Siberian roe deer) X = SM, Y ?*** 8 Mazama gouazoubira (G.