Genetic management of a water monitor lizard (Varanus salvator macromaculatus) population at Bang Kachao Peninsula as a consequence of urbanization with Varanus Farm Kamphaeng Saen as the first captive research establishment

Abstract

Water monitors (Varanus salvator macromaculatus) are large lizards that inhabit wetlands. However, populations seem to be declining due to habitat fragmentation resulting from urban development. To develop an effective strategic conservation plan, the genetic diversity and population structure of water monitors at Bang Kachao Peninsula, a rich urban ecosystem in Bangkok, were analyzed using mitochondrial (mt) D‐loop II sequences and microsatellite genotyping. Both genetic markers indicated a high degree of population‐level genetic diversity. The consistency of the star‐shaped haplotype network and results of neutrality tests strongly suggest the occurrence of a recent expansion in the population, possibly driven by anthropogenic urbanization. Subpopulations at Bang Kachao Peninsula are unlikely but gene flow between water monitors has occurred, which is suggestive of female‐based dispersal. The large population of water monitors at Bang Kachao Peninsula creates conflict with local residents. Long‐term population management through translocation has been conducted by captive management at Varanus Farm Kamphaeng Saen. The results of genetic monitoring indicate that the captive research population was soundly established. Comparison of allelic profiles between the two populations is necessary before translocation of water monitor groups from Bang Kachao Peninsula to Varanus Farm Kamphaeng Saen to reduce human‐wildlife conflict. This work is the first step toward establishment of long‐term ecological monitoring and an in situ/ex‐situ conservation program, which are part of attempts to promote biodiversity in Thailand, following scientific principles.

Concerted and Independent Evolution of Control Regions 1 and 2 of Water Monitor Lizards (Varanus salvator macromaculatus) and Different Phylogenetic Informative Markers

“…Blood specimens of water monitors ( V. salvator macromaculatus ) were collected from the ventral tail vein using a 23-gauge needle attached to a 2 mL disposable syringe containing 10 mM ethylenediaminetetraacetic acid for DNA extraction as previously reported by Wongtienchai et al [ 5 ] ( Supplementary Table S1 ). Samples were collected from 47 individuals at the Bang Kachao Peninsula, Samut Prakan, (13°59′2″ N, 99°59′38″ E) and from 25 individuals at Varanus Farm Kamphaeng Saen, Nakhon Pathom (14°00′59.9″ N, 99°57′46.8″ E).…”

“…Polymerase chain reaction (PCR) amplification was performed using 20 μL of 1× ThermoPol buffer containing 1.5 mM MgCl 2 , 0.2 dNTPs, 5.0 μM primers, 0.5 U of Taq polymerase (Apsalagen Co., Ltd., Bangkok, Thailand), and 25 ng of genomic DNA. The PCR conditions were as follows: initial denaturation at 94 °C for 3 min, followed by 35 cycles at 94 °C for 30 s, 57 °C for 30 s, and 72 °C for 40 s, and a final extension at 72 °C for 5 min [ 5 ]. The PCR products were separated via electrophoresis on 1% agarose gels, and they were then cloned using the pGEM ® -T Easy vector (Promega Corporation, Madison, WI, USA).…”

“…The mtCR plays an important role in transcriptional and translational regulation of protein-coding sequences, or it serves as the origin of DNA replication [ 2 ]. The nucleotide CR sequence is the most rapidly evolving region of the mitogenome, and it lacks coding sequences; thus, it is widely used as a molecular marker in population genetics, phylogenetic studies, and phylogeographic studies [ 3 , 4 , 5 ]. Vertebrates such as birds, snakes, turtles, and fish exhibit segmental duplications within the CR or an entire duplication of the CR, leading to the formation of repeats or possible homogenization between the duplicated copies of CR [ 6 , 7 , 8 ].…”

“…The presence of duplicate CRs in varanid mitogenomes is an intriguing structural phenomenon and raises basic questions concerning how the nucleotide sequences of duplicate CRs remained similar over time. Variations in CRs at the population and species level in varanids have not been fully elucidated [ 5 , 17 ]. In light of this scenario, we propose two hypotheses: (1) orthologous copies of duplicate CRs in different individuals are genetically similar due to independent evolution, or (2) two CRs (CR1 and CR2) as paralogous copies exhibit identical or highly similar nucleotide sequences from concerted evolution.…”

Reduced genetic variability in a captive-bred population of the endangered Hume’s pheasant (Syrmaticus humiae, Hume 1881) revealed by microsatellite genotyping and D-loop sequencing

“…We followed the same approaches as those used in previous studies of Asian woolly-necked stork (Ciconia episcopus, Boddaert 1783), Chinese goral (Naemorhedus griseus, Milne-Edwards 1871), and water monitor lizards (Varanus salvator macromaculatus, Laurenti 1768) [13][14][15][16]. Allelic frequency, number of alleles (A), effective number of alleles (N a ), observed heterozygosity (H o ), expected heterozygosity (H e ), and linkage equilibrium were calculated using Arlequin version 3.5.2.2 [17].…”