Related Experiment Video
Updated: Jun 12, 2026
06:00
Experimental Manipulation of Body Size to Estimate Morphological Scaling Relationships in Drosophila
Published on: October 1, 2011
Genetic and Environmentally Induced Scalation Variation in Bisexual and Parthenogenetic Lizards
David Tarkhnishvili1, Evsey Kosman2, Natia Barateli1
1Caucasus Leibniz Biodiversity Research Center, Ilia State University, 3/5 Cholokashvili Ave., Tbilisi 0162, Georgia.
Biology
|June 11, 2026
Summary
Parthenogenetic rock lizards, despite lacking genetic recombination, show adaptability comparable to sexual species. Phenotypic plasticity may compensate for limited genetic diversity, aiding survival in changing environments.
Area of Science:
- Evolutionary Biology
- Herpetology
- Genetics
Background:
- Parthenogenetic organisms typically have limited adaptive potential due to lack of recombination.
- Some parthenogenetic species, like Darevskia rock lizards, exhibit remarkable long-term survival.
- Phenotypic variation is explored as a potential mechanism for adaptation in asexual lineages.
Purpose of the Study:
- To compare genetic and phenotypic variability between a parthenogenetic lizard (Darevskia dahli) and its sexual ancestor (D. portschinskii).
- To investigate the role of phenotypic plasticity in the adaptation of parthenogenetic Darevskia lizards.
Main Methods:
- Comparative analysis of genetic and phenotypic variability.
- Study included 186 individuals of parthenogenetic D. dahli and 54 of sexual D. portschinskii.
- Phenotypic variability measured using KW dispersion and normalized effective number of individuals per metapopulation.
Main Results:
- D. portschinskii exhibited higher genetic variability than D. dahli.
- Phenotypic variability was similar between the two species.
- Parthenogenetic lizard phenotypes correlated with geographic distance and annual rainfall, with more outliers observed.
Conclusions:
- Phenotypic plasticity appears to be a key adaptation strategy for parthenogenetic rock lizards.
- This plasticity may compensate for the lack of genetic diversity, enabling survival.
- The findings offer insights into the long-term evolutionary success of asexual vertebrates.
Related Concept Videos
01:46Types of Selection
Natural selection influences the frequencies of particular alleles and phenotypes within populations in several different ways. Primarily, natural selection can be directional, stabilizing, or disruptive. Directional selection favors one extreme trait and shifts the population towards that phenotype while selecting against individuals displaying alternate traits. Stabilizing selection favors an intermediate trait with a narrow range of variation. Deviation from the optimal phenotype towards an...
02:16Genetics of Speciation
Speciation is the evolutionary process resulting in the formation of new, distinct species—groups of reproductively isolated populations.The genetics of speciation involves the different traits or isolating mechanisms preventing gene exchange, leading to reproductive isolation. Reproductive isolation can be due to reproductive barriers that have effects either before or after the formation of a zygote. Pre-zygotic mechanisms prevent fertilization from occurring, and post-zygotic mechanisms...
02:27Background and Environment Affect Phenotype
Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as temperature, oxygen availability, presence of mutagens, that can alter an organism’s phenotype.
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
01:31Formation of Species
Speciation describes the formation of one or more new species from one or sometimes multiple original species. The resulting species are discrete from the parent species, and barriers to reproduction will typically exist. There are two primary mechanisms, speciation with and without geographic isolation—allopatric and sympatric speciation, respectively.Allopatric SpeciationIn allopatric speciation, gene flow between two populations of the same species is prevented by a geographic barrier, like...
01:07Speciation Rates
Speciation can proceed at markedly different rates, and evolutionary biologists commonly describe these differences through the models of gradualism and punctuated equilibrium. Both patterns explain how new species arise, but they differ in the tempo and continuity of evolutionary change. In both cases, evolutionary change arises from heritable variation within populations, with natural selection often shaping traits that improve survival and reproduction under specific environmental conditions.
02:45The Ratio of X Chromosome to Autosomes
In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined by the ratio of the number of X chromosomes to the number of sets of autosomes. The Y chromosome in Drosophila is active but does not determine sex. It contains genes responsible for the production of sperms in adult flies.
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...