Karyotype Determination of Rock Hyrax Procavia Capensis in Saudi Arabia

© 2015 The Japan Mendel Society Cytologia 80(3): 287–293 Karyotype Determination of Rock Hyrax Procavia capensis in Saudi Arabia Saud A. Al-Dakan and Abdulaziz A. Al-Saleh* Zoology Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia Received November 1, 2014; accepted May 31, 2015 Summary Procavia capensis is considered as a small mammalian animal which belongs to order Hyracoidea, and it is the only species of the order that has been found in Saudi Arabia. Therefore, karyotype analysis of this species has been carried out and the finding summarized as follows. The diploid chromosome number is 54. In the karyotype analysis, the somatic chromosomes were catego- rized into three groups: 21 pairs of acrocentric, 2 pairs of submetacentric and 3 pairs of metacentric chromosomes. The sex chromosomes are one submetacentric X chromosome and one acrocentric Y chromosome. The lengths of chromosomes varied between 1.6–7.6 µm, and the Y chromosome is the shortest. The FN is 65 in the male and 66 in the female, while the FNa is 62. The karyotype formula of Procavia capensis could be deduced as: a sm a sm a sm m (2=54);Ln 14+ L 1 + M 14 + M 2 ++ S 15 S 2 + S 6 Key words Karyotype, Rock hyrex, Chromosome, Procavia capensis. The rock hyrax (Procavia capensis) is one of small mammalian herbovorous animals that lives in small family groups ranging from 10 to 80 members headed by a dominant adult male which defends and watches over the group (Turner and Watson 1965, Grzimek 1975, Skinner and Smithers 1990, Estes 1991, Kingdon 1991, Manharth and Harris-Gerber 2002). This animal belongs to the Ungulates family and feeds on a wide variety of different plants including both grasses and shrub leaves and sometimes eats insects and lizards (Burton 1941, Grzimek 1975). The rock hyrax is found across Africa, the Middle East and particularly in the Arabian Pen- insula and the Levant, including Syria, Palestine and Jordan (Kingdon 1971). Procavia capensis is the only species found in the kingdom of Saudi Arabia (Kingdon 1990). This species spreads in the Kingdom of Saudi Arabia in the mountainous regions of Sarawat Mountains in the western region and in the chain Twaiq Mountains in Najd Plateau (Gasperetti 1978, Vincett 1982, Kingdon 1990, Nader 1990, Harrison and Bates 1991, Kamal 1996). It also lives in the middle of vegetation and hides in caves and rock crevices and cavities because it needs secure shelter, but does not reside in burrows because it is unable to dig burrows and cannot drill (Hoeck 1975, Olds and Shoshani 1982, Estes 1991). The rock hyrax can climb rocks skillfully, as the rest of its feet have cushions containing sweat glands that excrete an adhesion solution, enabling it to climb smooth rocks (Bar- tholomew and Rainy 1971, Olds and Shoshani 1982, Estes 1991). This animal is important because it is much like a rabbit but mostly larger, has sometimes weighed up to 5 kg, and is always vulnerable to hunting for the purpose of eating or for medical purposes in some cases. In folk medicine, the animal waste from feces and urine, known as hyra- ceum, is used in the treatment of epilepsy and some women’s diseases (Olds and Shoshani 1982, * Corresponding author, e-mail: [email protected] DOI: 10.1508/cytologia.80.287 288 S. A. Al-Dakan and A. A. Al-Saleh Cytologia 80(3) Kraemer 2001). The rock hyrax also is a natural reservoir or favorite host for Leishmania which causes skin Coetaneous leishmaniasis and the infection incidence with this parasite might reach up to 80% (Talmi-Frank et al. 2010). There are also those who believe that the animal can be used like an animal laboratory to conduct some scientific experiments, where it lives under captivity for a period of 12 years (Griner 1968, Fourie 1978). This animal is devastating agricultural crops, particularly fruit trees. Therefore, it is included under harmful or vermin animals and in some areas, electric fences are placed to eliminate the animal (Hanse 1962). Due to the economic and medical importance of this animal and the lack of studies on its chromosomal patterns, we determined to study the nature of the chromosomal pattern and es- tablish its karyotype as the first study to performed on this species from the Kingdom of Saudi Arabia. Materials and methods Ten adult males and 10 adult females were collected from the central province and the south- ern province of the Kingdom of Saudi Arabia and were kept in a room containing some rocks and fresh branches of Acacia. Each animal was injected with intraperitoneal with 2 mL colchicine solution (1 mg mL－1) and kept for 4–6 h before the animal was sacrificed. The femoral bones were re- moved and their bone marrow was flushed with 7 mL of hypotonic solution (0.56% potassium chlo- ride). The bone marrow cells were suspended very well and cells kept in the hypotonic solution for 30 min at 37°C. The bone marrow cells were centrifuged at 1000 rpm for 5 min and the cell pellet was suspended in 7 mL of fresh fixative (3 : 1 methanol–acetic acid). The fixation procedure was re- peated twice and finally the cells were fixed in 2 mL of fresh fixative. One drop of cells was spread onto the microscopic slide. The cells were stained with 5% Giemsa stain for 5 min and left to dry completely before examination. More than 100 metaphase stages have been scanned for each male and female under Zeiss microscope provided with digital imaging high-resolution camera. Good metaphase stages were selected, photographed under immersion oil lens and mounted into the computer for analysis. The length of the arms of the chromosomes was measured directly under the microscope using an ocular eyepiece with reticule, and the centromeric position and relative arms length were calculated using the terminology described by Levan et al. (1964). The fundamental number of the chromosomes or the number of arms of the chromosomes was calculated according to the hypothesis of Matthey (1945). Results In this study, the chromosomes of the male and female rock hyrax Procavia capensis have been identified and described. The rock hyrax animals that have been collected from the Riyadh and Mecca provinces are technically the same except that the animals collected from Riyadh province are light brown (Fig. 1), while those obtained from Mecca province are dark brown and the blackness is due to the black color of the mountains of the province (Fig. 2). Figures 3 and 4 show the karyotype of the male and female Procavia capensis, respectively. The karyotype consists of a diploid number (2n)=54 chromosomes. These chromosomes are 21 pairs of acrocentric (1–21), 2 pairs of submetacentric (22–23) and 3 pairs of metacentric chromosomes (24–26). The sex chromosomes are one metacentric X chromosome and one acrocentric Y chromosome. The measurement of the length of the chromosomes was calculated from five different karyo- types and the relative length represented in Table 1. Acrocentric chromosomes were classified according to their length into three types: 1) Chromosomes 1–7 are large-size chromosomes; 2) Chromosomes 8 to 14 are medium-size chromosomes; 3) Chromosomes 15 to 21 are small-size 2015 Karyotype Determination of Rock Hyrax Procavia capensis in Saudi Arabia 289 Fig. 1. Rock hyrax from Riyadh province. Fig. 2. Rock hyrax from Mecca province. Table 1. Mean length of the total chromosome length, length of its arms and the type of centromeres of Procavia capensis. No. Short arm P Long arm Q Total length p+q Arm ratio q/p Centromere 1 1.1 6.5 7.6 6.0 a 2 1.0 5.8 6.8 5.8 a 3 1.1 5.4 6.5 4.9 a 4 1.1 5.3 6.4 4.8 a 5 1.0 4.9 5.9 4.9 a 6 1.1 4.3 5.4 3.9 a 7 1.0 4.2 5.2 4.2 a 8 1.0 3.8 4.8 3.8 a 9 0.8 3.8 4.6 5.3 a 10 0.6 3.2 3.8 5.3 a 11 0.6 3.0 3.6 5.0 a 12 0.6 3.0 3.6 5.0 a 13 0.6 2.9 3.5 4.8 a 14 0.7 2.5 3.2 3.6 a 15 0.6 2.3 2.9 3.8 a 16 0.5 2.3 2.8 4.6 a 17 0.5 2.2 2.7 4.4 a 18 0.5 1.9 2.4 3.8 a 19 0.3 1.9 2.2 6.3 a 20 0.5 1.6 2.1 3.2 a 21 0.3 1.7 2.0 5.6 a 22 2.0 4.5 6.5 2.2 sm 23 1.3 3.5 5.0 2.3 sm 24 1.3 1.4 2.7 1.1 m 25 1.2 1.3 2.5 1.1 m 26 1.1 1.2 2.3 1.1 m X 1.8 4.2 6.0 2.3 sm Y 0.0 1.6 1.6 ∞ a Metacentric (m)=1–1.69; Submetacentric (sm)=1.7–3.00; Acrocentric (a)=3.1–∞. chromosomes. The submetacentric chromosomes are classified according to the length into two types: 1) Chromosome 22 is a medium-size chromosome; 2) Chromosome 23 is a small-size chromosome.

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