Morphological variation and sex dimorphism in adult Аzov Yellow-legged Gull Larus cachinnans сachinnans

Gulls were trapped in the breeding colony on islands of Molochny Liman, a salt reservoir near the north Azov seashore (south of Zaporizhzhia Region, Ukraine). The total of measured cachinnans is 80 birds, more than 3500 nestlings were ringed. For trapped birds a total of 28 parameters were taken (14 metrical and 14 colour features). Blood samples were obtained from the most of the captured birds for further genetical analysis, and pictures were taken to record coloration (colour of eyes, legs, mantle, etc.).Исследования проводились в 2000-2001 гг. на юге Запорожской области, на о-вах Молочного лимана Азовского моря. Сетевыми ловушками типа «цилиндр» было отловлено, прижизненно обследовано и окольцовано 80 экз. взрослых чаек, окольцовано свыше 3500 подросших птенцов. Измерения проводились по 28 параметрам (14 метрических и 14 цветовых). Брались пробы крови из ножной вены для последующего генетического анализа, проведена цветная фотосъемка внешнего вида чаек (окраска глаз, ног, мантии и др.).Дослідження проводилися в 2000-2001 рр. на півдні Запорізької області, на о-вах Молочного лиману Азовського моря. Сітковими пастками типу «циліндр» було виловлено, прижиттєво обстежено та закільцьовано 80 екз. дорослих мартинів, закільцьовано понад 3500 підрослих пташенят. Виміри проводилися згідно з 28 параметрами (14 метричних і 14 колірних). Бралися проби крові з ножною вени для подальшого генетичного аналізу, проведена кольорова фотозйомка зовнішнього вигляду чайок (забарвлення очей, ніг, мантії та ін.)

Genotyping of black grouse MHC class II B using reference Strand-Mediated Conformational Analysis (RSCA)

<p>Abstract</p> <p>Background</p> <p>The Major Histocompatibility Complex (MHC) is a cluster of genes involved in the vertebrate immune system and includes loci with an extraordinary number of alleles. Due to the complex evolution of MHC genes, alleles from different loci within the same MHC class can be very similar and therefore difficult to assign to separate loci. Consequently, single locus amplification of MHC genes is hard to carry out in species with recently duplicated genes in the same MHC class, and multiple MHC loci have to be genotyped simultaneously. Since amplified alleles have the same length, accurate genotyping is difficult. Reference Strand-Mediated Conformational Analysis (RSCA), which is increasingly used in studies of natural populations with multiple MHC genes, is a genotyping method capable to provide high resolution and accuracy in such cases.</p> <p>Findings</p> <p>We adapted the RSCA method to genotype multiple MHC class II B (BLB) genes in black grouse (<it>Tetrao tetrix</it>), a non-model galliform bird species, using a 96-Capillary Array Electrophoresis, the MegaBACE™ 1000 DNA Analysing System (GE Healthcare). In this study we used fluorescently labelled reference strands from both black grouse and hazel grouse and observed good agreement between RSCA and cloning/sequencing since 71 alleles were observed by cloning/sequencing and 76 alleles by RSCA among the 24 individuals included in the comparison. At the individual level however, there was a trend towards more alleles scored with RSCA (1-6 per individual) than cloning/sequencing (1-4 per individual). In 63% of the pair-wise comparison, the identical allele was scored in RSCA as in cloning/sequencing. Nine out of 24 individuals had the same number of alleles in RSCA as in cloning/sequencing. Our RSCA protocol allows a faster RSCA genotyping than presented in many other RSCA studies.</p> <p>Conclusions</p> <p>In this study, we have developed the RSCA typing method further to work on a 96-Capillary Array Electrophoresis (MegaBACE™ 1000). Our RSCA protocol can be applied to fast and reliable screening of MHC class II B diversity of black grouse populations. This will facilitate future large-scale population studies of black grouse and other galliformes species with multiple inseparable MHC loci.</p

Speciation with gene flow in the large white-headed gulls: does selection counterbalance introgression?

International audienceWe investigated the role of selection in generating and maintaining species distinctness in spite of ongoing gene flow, using two zones of secondary contact between large gull species in Europe (Larus argentatus and Larus cachinnans) and North America (Larus glaucescens and Larus occidentalis). We used the pattern of neutral genetic differentiation at nine microsatellite loci (F(ST)) as an indicator of expected changes under neutral processes and compared it with phenotypic differentiation (P(ST)) for a large number of traits (size, plumage melanism and coloration of bare parts). Even assuming very low heritability, interspecific divergence between L. glaucescens and L. occidentalis in plumage melanism and orbital ring colour clearly exceeded neutral differentiation. Similarly, melanism of the central primaries was highly divergent between L. argentatus and L. cachinnans. Such divergence is unlikely to have arisen randomly and is therefore attributed to spatially varying selection. Variation in plumage melanism in both transects agrees with Gloger's rule, which suggests that latitude (and associated sun and humidity gradients) could be the selective pressure shaping differentiation in plumage melanism. We suggest that strong species differentiation in orbital ring colour results from sexual selection. We conclude that these large gull species, along with other recently diverged species that hybridize after coming into secondary contact, may differ only in restricted regions of the genome that are undergoing strong disruptive selection because of their phenotypic effects

Molecular and morphological patterns of introgression between two large white-headed gull species in a zone of recent secondary contact

Incomplete reproductive isolation promotes gene flow between diverging taxa. However, any gene encoding for traits involved in the reproductive barriers will be less prone to introgression than neutral markers. Comparing introgression rates among loci is thus informative of the number and functions of loci involved in the reproductive barriers. This study aimed at identifying possible mechanisms of restriction to gene flow across a zone of recent secondary contact between Larus argentatus and Larus cachinnans by comparing introgression patterns for nine microsatellite loci, a fragment of mitochondrial DNA and a set of phenotypic traits. The low linkage disequilibrium between neutral nuclear markers indicated introgression without any barrier to gene flow. However, asymmetric introgression of mitochondrial DNA suggested that interspecific crosses may be more successful in one direction. The introgression rate for phenotypic traits was variable and low compared to neutral molecular markers. This was particularly evident in colouration of bare parts: individuals with intermediate colouration were scarcer in sympatry than expected if the genomes recombined freely. We hypothesized that one of these variables, the orbital ring colour, may play a role in mate choice, acting as an incomplete premating barrier through assortative mating. This study emphasizes that multilocus approaches are useful to discriminate among possible mechanisms responsible for the maintenance of hybrid zones

Habitat shapes diversity of gut microbiomes in a wild population of blue tits Cyanistes caeruleus

Microbiome constitutes an important axis of individual variation that, together with genes and the environment, influences an individual's physiology and fitness. Microbiomes are dependent not only on an individual's body condition but also on external factors, such as diet or stress levels, and as such can be involved into feedbacks between the external ecological factors and internal physiology. In our study, we used a wild population of blue tits Cyanistes caeruleus to investigate the impact of external habitat composition on the microbiome of adult birds. We hypothesized that - through differences in plant composition, potentially affecting diet complexity - habitat type may impact the diversity and structure of the gut microbiome. Blue tits breeding in dense deciduous forests tended to have more diverse microbiomes and be significantly different in terms of microbiome composition from birds breeding in open, sparsely forested hay meadows. Distinct study plots also tended to differ in a number of parameters describing microbiome diversity. We observed no microbiome differentiation according to individual characteristics such as sex or age. The study emphasizes that external environment is one of the important modulators of microbiome diversity and calls for more such studies in wild animal populations