Identifying priority areas for the conservation of the Critically Endangered northern white-cheeked gibbon Nomascus leucogenys in northern Lao

All gibbon species are declining throughout South and South-east Asia because of habitat loss and human activities such as hunting. Lao still contains a relatively large area of forest habitat suitable for gibbons, but their status in the country remains poorly known. Here we present the first density estimate of the Critically Endangered northern white-cheeked gibbon Nomascus leucogenys in Nam Et-Phou Louey National Protected Area, northern Lao. We conducted gibbon surveys using an auditory sampling technique during May–August 2014 and May 2015, at 40 sites, covering 125.6 km2. We applied N-mixture models to analyse group counts, investigating which landscape and human disturbance covariates influenced the spatial variation of gibbon abundance across the study area. We estimated the average gibbon density to be 0.4 groups/km2. Gibbon density was higher in mixed deciduous forest (0.74 groups/km2) than in evergreen forest (0.09 groups/km2), which could be a result of long-term hunting in evergreen forest areas. Thus, future gibbon protection plans should consider not only evergreen forest as priority habitat, but also deciduous forest, which tends to receive less attention in conservation planning. We also highlight key areas containing gibbons where law enforcement patrols should be focussed, to limit threats such as poaching. Future forest management plans should aim to maximize the size and connectivity of suitable gibbon habitat, to enable exchange between subpopulations.

Identification and analysis of mobile genetic elements in Gibbon genome

Recent sequencing of genome of northern white-cheeked gibbon (Nomascus leucogenys) has provided important insight into fast evolution of gibbons and signatures relevant to gibbon biology. It was revealed that mobile genetic elements (MGE) seems to play major role in gibbon evolution. Here we report that most of the gibbon genome is occupied by the MGEs such as ALUs, MIRs, LINE1, LINE 2, LINE 3, ERVL, ERV-class1, ERV-class II and other DNA elements which include hAT Charlie and TcMar tigger. We provide detailed description and genome wide distribution of all the MGEs present in gibbon genome. Previously, it was reported that gibbon-specific retrotransposon (LAVA) tend to insert into chromosome segregation genes and alter transcription by providing a premature termination site, suggesting a possible molecular mechanism for the genome plasticity of the gibbon lineage. We show that insertion sites of LAVA elements present atypical signals/patterns which are different from typical signals present at insertion sites of Alu elements. This suggests possibility of distinct insertion mechanism used by LAVA elements for their insertions. We also find similarity in signals of LAVA elements insertion sites with atypical signals present at Alus /L1s insertion sites disrupting the genes leading to diseases such as cancer and Duchenne muscular dystrophy. This suggest role of LAVA in premature transcription termination.