Shorebirds’ Longer Migratory Distances Are Associated With Larger ADCYAP1 Microsatellites and Greater Morphological Complexity of Hippocampal Astrocytes

Abstract

For the epic journey of autumn migration, long-distance migratory birds use innate and learned information and follow strict schedules imposed by genetic and epigenetic mechanisms, the details of which remain largely unknown. In addition, bird migration requires integrated action of different multisensory systems for learning and memory, and the hippocampus appears to be the integration center for this task. In previous studies we found that contrasting long-distance migratory flights differentially affected the morphological complexity of two types of hippocampus astrocytes. Recently, a significant association was found between the latitude of the reproductive site and the size of the ADCYAP1 allele in long distance migratory birds. We tested for correlations between astrocyte morphological complexity, migratory distances, and size of the ADCYAP1 allele in three long-distance migrant species of shorebird and one non-migrant. Significant differences among species were found in the number and morphological complexity of the astrocytes, as well as in the size of the microsatellites of the ADCYAP1 gene. We found significant associations between the size of the ADCYAP1 microsatellites, the migratory distances, and the degree of morphological complexity of the astrocytes. We suggest that associations between astrocyte number and morphological complexity, ADCYAP1 microsatellite size, and migratory behavior may be part of the adaptive response to the migratory process of shorebirds.

Urbanization is associated with non‐coding polymorphisms in candidate behavioural genes in the Eurasian coot

“…In contrast to our results, previous studies on blackbirds revealed relationships of habitat urbanization level with polymorphisms at both of these genes, although they were relatively weak (Mueller et al, 2013). ADCYAP1 was also reported to associate with migratory propensity, distance and restlessness in birds (de Almeida et al, 2022;Mueller et al, 2011). Similarly, relationships between DRD4 gene polymorphism and exploratory behaviour were found in several passerine bird species (e. g. Garamszegi et al, 2014;Mueller et al, 2014) co-regulate gene expression, than in coding gene regions, where non-silent mutations introduce alterations in protein structure.…”

Dissecting Reactive Astrocyte Responses: Lineage Tracing and Morphology-based Clustering

“…Finally, in this work we are pioneers in establishing a method to classify astrocytes based on their morphology changes in response to injury, correlating different morphological parameters with their intensity of the response. Previous works have introduced this type of approaches to study neuronal subpopulations for example in the nucleus of the solitary tract (Schweitzer et Renehan, 1997) or to categorize diverse subpopulations of hippocampal astrocytes in migratory birds (Carvalho-Paulo et al, 2018;Henrique et al, 2021;de Almeida et al, 2022), reactive microglia in models of encephalitis (de Sousa et al, 2015;da Silva Creão et al, 2021) or in models of neuroinflammation (Fernández-Arjona et al, 2017); and immune cells in starfishes (Karetin, 2021). Here, we developed a multimodality index (MMI) to select parameters that best describe the population heterogenicity, and subsequently applied hierarchical clustering (HC), and principal component analysis (PCA) to identify and construct a dendrogram of reactive responses.…”

Time trees and clock genes: a systematic review and comparative analysis of contemporary avian migration genetics

“…More recently, however, several authors have questioned the suitability of the Mantel test in such applications (Guillot & Rousset, 2013; Legendre, Fortin & Borcard, 2015) as this test is designed to compare two distance matrices that both measure differences rather than physical distance and argued that geographic distance expressed in kilometres may exaggerate the relationship. Other potential confounding issues include the post‐hoc grouping of study individuals based on observed outlier status (Bazzi et al ., 2015) or sex (Dor et al ., 2011) rather than predetermined grouping, small sample sizes (de Almeida Miranda et al ., 2022), and the averaging of alleles in heterozygotes to analyse mean allele length (Zhang et al ., 2017).…”

“…A recent study (de Almeida Miranda et al ., 2022) assessed diversity within Adcyap1 in several species of shorebirds: the collared plover, Charadrius collaris (Vieillot), semipalmated sandpiper, Calidris pusilla (Linnaeus), semipalmated plover, Charadrius semipalmatus (Bonaparte), and spotted sandpiper, Actitis macularius (Linnaeus). They found several alleles for each species but the study was limited in its resolution by small sample sizes.…”