Surveying Neurergus in Iran 

 

neurergus.org

 

Population genetics

Population genetics is concerned with the study of the genetic variation of populations. Genetic variation with populations may be changed by fragmentation, selection, mutation, recombination, mating structure, migration, and other genetic, ecological, and evolutionary factors. Population genetics investigates these mechanisms and their interactions and evolutionary consequences. Recently population genetics has been applied to ecology and conservation biology, particularly in respect to meta-population analysis and to identify sub-populations of conservation concern.

Population genetics also has important interfaces with molecular biology, systematics, taxonomy, mathematics, statistics, and computing. One of the main subjects of population genetics is the investigation of the mechanisms that generate and maintain genetic variability in populations, and the study of how this genetic variation, shaped by environmental influences, leads to evolutionary change, adaptation, and speciation.

“Newts of the Middle Eastern genus Neurergus (Salamandridae) have been considered to comprise four species: N. strauchii (Steindachner, 1887), (N.s. strauchii and N. s. barani, Öz , 1994), N. crocatus (Cope, 1862 ), N. microspilotus (Nesterov, 1917 ) and N. kaiseri (Schmidt, 1952). Schmidtler and Schmidtler (1970, 1975) and (Schmidtler, 1994) considered that all Neurergus species can be easily distinguished on morphological and biogeographic bases.

However, the status of N. microspilotus and N. barani has recently been questioned. Possibilities are that the name N. barani takes precedence over N. microspilotus, N. microspilotus becomes a sub-species of N. barani, or the two are different species (Schneider and Schneider, 2011). This uncertainty is under ongoing genetic research.

There have been no fine scale molecular studies (ie. using microsatellites) to study a genetic relatedness within Neurergus species.” 

Population genetics is the study of the range of genetic variation of a species and its distribution across, between, and within populations. 

Population genetics can inform conservation biologists of genetic sub-populations, migration rates between sub-populations, population bottlenecks, parentage and effective population size. This information can then be used in field conservation to identify sources and sinks within meta-populations and to identify significant genetic sub-populations. 

This information prioritises the use of conservation resources in the management of threatened species to maintain genetic variation in nature and to guide the sampling of natural populations for both individuals and for gene banking in the ex situ facets of conservation breeding programs.

In taxon management program the traditional genetic unit is the species. Different populations of a species may have different colour and morphology but be the same genetically, or as cryptic species appear the same morphologically but be distinct genetically. Consequently, even well studied populations once considered as one species have recently turned out to be two or more. The use of mitochondrial DNA inherited through the female lineage can tell when species formed and their distinctiveness from other species.

However, even well defined species sometimes form different populations that may develop different genetic characteristics. If these genetic differences are great enough these sub-populations may be considered Ecologically Significant Units (ESUs). ESUs may have unique characteristics that favour their survival in particular environments.

Not identifying ESUs is will increase the probability of conservation breeding programs failing to provide genetically competent individuals for restocking. Conservation programs could also fail to maintain habitats important to particular ESUs.

Other more general genetic problems are inbreeding and out breeding depression that can occur in the management of both natural and captive populations.

In breeding depression occurs when a loss of genetic variation, sometimes accompanied by an increase in deleterious genes, results in poor health and reproduction. Out breeding depression occurs when genes that do not benefit survival are introduced into a population.

To prevent these problems, conservation projects must first be confident of the genetic status of the functional conservation unit. Check the species over the web through search “Species, phylogeny, taxonomy, mitochondrial DNA”.  Then consult with someone expert in the field such as a museum curator, taxonomist, or a genetics researcher. You can often find these through the articles corresponding author. Often the mitochondrial DNA work has been done. However, assessing the population genetics will usually be more difficult and require about 30 samples from each possible ESU and probably a masters or PhD to complete.

There are many institutions that teach or conduct genetics such as universities, museums and zoos. If you can guarantee the samples, that the project is important, the project is interesting; these institutions will often support the project. Mitochondrial DNA work is very easy if only species level assessment is required.

 Species knowledge

The first step in any taxon based conservation plan is to specify the functional unit you wish to conserve. Typically this unit is a species. However, because species are continuously evolving, over distinct evolutionary significant units (ESU) that warrant special conservation measures. Genetics is used to separate species, and ESUs within species.

Different populations or individuals within species might appear different in their colour and morphology but be the same genetically, or appear the same morphologically as cryptic species but be distinct genetically. Consequently, even well studied populations considered as one species have recently turned out to be two or more. 

Therefore, the minimum study required is of mitochondrial DNA, which will tell how divergent the species are, and by molecular clocks how long ago they diverged. More elaborate studies of population genetics will distinguish ESUs. New species are often revealed by different calls from similar looking amphibians, and the chance of new ESUs in the increasing length of isolation of between populations of a species.

Not identifying ESUs is will increase the probability of conservation breeding programs failing to provide genetically competent individuals for restocking. We could also miss conserving the habitat of a cryptic species.  Other more general genetic problems are inbreeding and out breeding depression. In breeding depression occurs when a loss of genetic variation, often accompanied by an increase in deleterious genes, results in poor health and reproduction. Out breeding depression occurs when genes that do not benefit survival are introduced into a population. These can occur in both captive populations and those in nature.

To prevent these problems, conservation projects must first be confident of the genetic status of the functional conservation unit. Check the species over the web through search “Species, phylogeny, taxonomy, mitochondrial DNA”.  Then consult with someone expert in the field such as a museum curator, taxonomist, or a genetics researcher. You can often find these through the articles corresponding author. Often the mitochondrial DNA work has been done. However, assessing the population genetics will usually be more difficult and require about 30 samples from each possible ESU and probably a masters or PhD to complete.

There are many institutions that teach or conduct genetics such as universities, museums and zoos. If you can guarantee the samples, that the project is important, the project is interesting, these institutions will often support the project. The mitochondrial DNA work is quite easy if only species level assessment is required.