Loci de rasgos binarios que influyen en la expresión del comportamiento higiénico de las abejas melíferas

This study was conducted to detect binary trait loci (BTLs) that influence the expression of hygienic behavior of individual honey bee workers and to locate genetic markers that are associated to these BTLs on a genetic map derived from bees that perform hygienic behavior of a backcross colony. Samples of workers that perform hygienic behavior and workers that not perform hygienic behavior that were used as controls were collected from the colony.Este estudio se realizó, para detectar loci de rasgos binarios (BTL) que influyen en la expresión del comportamiento higiénico de abejas obreras y para localizar marcadores genéticos asociados a estos BTL en un mapa de ligamiento. Se recolectaron abejas que realizaron el comportamiento higiénico y abejas que no realizaron el comportamiento higiénico de una colonia producto de una retrocruza. Se construyó, un mapa genético utilizando marcadores AFLP generados a partir del ADN de las abejas que realizaron el comportamiento higiénico

A Search for Parent-of-Origin Effects on Honey Bee Gene Expression

Parent-specific gene expression (PSGE) is little known outside of mammals and plants. PSGE occurs when the expression level of a gene depends on whether an allele was inherited from the mother or the father. Kin selection theory predicts that there should be extensive PSGE in social insects because social insect parents can gain inclusive fitness benefits by silencing parental alleles in female offspring. We searched for evidence of PSGE in honey bees using transcriptomes from reciprocal crosses between European and Africanized strains. We found 46 transcripts with significant parent-of-origin effects on gene expression, many of which overexpressed the maternal allele. Interestingly, we also found a large proportion of genes showing a bias toward maternal alleles in only one of the reciprocal crosses. These results indicate that PSGE may occur in social insects. The nonreciprocal effects could be largely driven by hybrid incompatibility between these strains. Future work will help to determine if these are indeed parent-of-origin effects that can modulate inclusive fitness benefits

Behavioral genomics of honeybee foraging and nest defense

The honeybee has been the most important insect species for study of social behavior. The recently released draft genomic sequence for the bee will accelerate honeybee behavioral genetics. Although we lack sufficient tools to manipulate this genome easily, quantitative trait loci (QTLs) that influence natural variation in behavior have been identified and tested for their effects on correlated behavioral traits. We review what is known about the genetics and physiology of two behavioral traits in honeybees, foraging specialization (pollen versus nectar), and defensive behavior, and present evidence that map-based cloning of genes is more feasible in the bee than in other metazoans. We also present bioinformatic analyses of candidate genes within QTL confidence intervals (CIs). The high recombination rate of the bee made it possible to narrow the search to regions containing only 17–61 predicted peptides for each QTL, although CIs covered large genetic distances. Knowledge of correlated behavioral traits, comparative bioinformatics, and expression assays facilitated evaluation of candidate genes. An overrepresentation of genes involved in ovarian development and insulin-like signaling components within pollen foraging QTL regions suggests that an ancestral reproductive gene network was co-opted during the evolution of foraging specialization. The major QTL influencing defensive/aggressive behavior contains orthologs of genes involved in central nervous system activity and neurogenesis. Candidates at the other two defensive-behavior QTLs include modulators of sensory signaling (Am5HT(7) serotonin receptor, AmArr4 arrestin, and GABA-B-R1 receptor). These studies are the first step in linking natural variation in honeybee social behavior to the identification of underlying genes

Genotypic variation in the expression of guarding behavior and the role of guards in the defensive response of honey bee colonies

This study was conducted to identify genotypic variation in the expression of guarding behavior between defensive and gentle backcross colonies and to determine the role of guards in the defensive response of a colony. No differences were found between backcross types for the average time that a bee behaves as a guard. Differences were found between backcross types and between colonies for the number of bees that guard for at least one day and for at least two days. Variation between colonies for these two variables was partially genetic in origin. A small proportion of the bees that stung during stinging assays were guards, and only a small proportion of the guards stung. Positive correlations were found between the number of stings and both the number of guards in the colony and the proportion of guards that stung in relation to the total number of guards in the colony. Colonies responded with fewer stings when guards were removed in comparison to when guards were present in the colonies

Relative effect of four characteristics that restrain the population growth of the mite Varroa destructor in honey bee (Apis mellifera) colonies

This study was conducted to determine the existence of phenotypic and genotypic variation in the ability of honey bee colonies to restrain the population growth of the mite Varroa destructor Anderson and Trueman, and to asses the relative effect of four characteristics that may confer tolerance to honey bees toward the mite. Fifty-eight colonies infested with an equal number of mites were sampled monthly during six months to determine their levels of infestation on adult bees and in worker brood. At the end of this period, 16 colonies were selected to study the effect of grooming behavior, hygienic behavior, brood attractiveness, and host-induced non-reproduction. The infestation-levels in adult bees varied significantly between colonies (range: 6.6-44.7% ), but no differences were found in the brood infestation levels. The variation between colonies was partially genetic in origin. Grooming behavior explained most of the variation ($r^2 = 0.38$). Negative correlations were found between the mite population growth and both the total number of mites and the number of injured mites collected from the bottom-boards ($r = -0.65$ and $r = -0.76$, respectively). Differences were found for hygienic behavior but the effect of this mechanism was not clear. No differences were found among colonies for brood attractiveness, or for the effect of the brood on the mite's reproduction

Características endocrinas, moleculares y de parámetros de crecimiento asociados a la obesidad del cerdo pelón mexicano

To establish the potential of the Mexican hairless pig as an animal model for the study of obesity, a comparative study between the Mexican hairless pigs (MHP) and Landrace-Yorkshire pigs (LYP) was performed. Leptin and insulin serum concentrations were measured and its correlation with backfat thickness was estimated. Feed intake, daily weight gain and backfat thickness was evaluated. Gene expression of leptin, leptin receptor, adiponectin and peroxisoma proliferator activated receptor gamma (PPAR-γ,) in adipose tissue were also evaluated. The LYP had a higher weight gain (P0.05). However, the backfat thickness was higher in the MHP (PPara determinar el potencial del cerdo Pelón Mexicano (CPM) en el estudio de la obesidad, se realizó un estudio entre el CPM y cerdos Landrace-Yorkshire (CLY). Se midieron concentraciones séricas de leptina e insulina y se determinó su correlación con el espesor de grasa dorsal (EGD). Se evaluó el consumo de alimento (CA), el EGD, la ganancia diaria de peso y la expresión de genes que codifican para leptina, el receptor de leptina, adiponectina y el receptor activado por proliferadores de peroxisomas gama (PPAR-γ,), mediante PCR de tiempo real. Los CLY tuvieron una ganancia de peso mayor (

Confirmation of QTL effects and evidence of genetic dominance of honey bee defensive behavior: Results of colony and individual behavioral assays

The stinging and guarding components of the defensive behavior of European, Africanized, hybrid, and backcross honeybees (Apis mellifera L.) were compared and analyzed at both colony and individual levels. Hybrid and Africanized backcross colonies stung as many times as Africanized ones. European backcross colonies stung more than European bees but not as many times as Africanized or Africanized backcross colonies. The degree of dominance for the number of times that worker bees stung a leather patch was estimated to be 84.3%, 200.8%, and 145.8% for hybrid, backcross European, and backcross Africanized colonies, respectively. Additionally, both guards at the colony entrance and fast-stinging workers of one European backcross colony had a significantly higher frequency of an Africanized DNA marker allele, located near “sting1,” a QTL previously implicated in stinging behavior at the colony level. However, guards and faststinging bees from a backcross to the Africanized parental colony did not differ from control bees in their frequency for the Africanized and European markers, as would be expected if large genetic dominance effects for sting1 exist. These results support the hypothesis that genetic dominance influences the defensive behavior of honeybees and confirm the effect of sting1 on the defensiveness of individual worker bees. KEY WORDS: Apis mellifera; defensive behavior; Africanized honeybees; genetic dominance; QTL

Fine-Scale Linkage Mapping Reveals a Small Set of Candidate Genes Influencing Honey Bee Grooming Behavior in Response to Varroa Mites

<div><p>Populations of honey bees in North America have been experiencing high annual colony mortality for 15–20 years. Many apicultural researchers believe that introduced parasites called Varroa mites (<em>V. destructor</em>) are the most important factor in colony deaths. One important resistance mechanism that limits mite population growth in colonies is the ability of some lines of honey bees to groom mites from their bodies. To search for genes influencing this trait, we used an Illumina Bead Station genotyping array to determine the genotypes of several hundred worker bees at over a thousand single-nucleotide polymorphisms in a family that was apparently segregating for alleles influencing this behavior. Linkage analyses provided a genetic map with 1,313 markers anchored to genome sequence. Genotypes were analyzed for association with grooming behavior, measured as the time that individual bees took to initiate grooming after mites were placed on their thoraces. Quantitative-trait-locus interval mapping identified a single chromosomal region that was significant at the chromosome-wide level (p<0.05) on chromosome 5 with a LOD score of 2.72. The 95% confidence interval for quantitative trait locus location contained only 27 genes (honey bee official gene annotation set 2) including <em>Atlastin</em>, <em>Ataxin</em> and <em>Neurexin-1 (AmNrx1)</em>, which have potential neurodevelopmental and behavioral effects. <em>Atlastin</em> and <em>Ataxin</em> homologs are associated with neurological diseases in humans. <em>AmNrx1</em> codes for a presynaptic protein with many alternatively spliced isoforms. <em>Neurexin-1</em> influences the growth, maintenance and maturation of synapses in the brain, as well as the type of receptors most prominent within synapses. <em>Neurexin-1</em> has also been associated with autism spectrum disorder and schizophrenia in humans, and self-grooming behavior in mice.</p> </div

Map of QTL location for groom-1 on chromosome 5.

<p>The physical location in base pairs of SNP probes in the honey bee genome assembly (Amel 4.0) is indicated to the right of the bar. The large number associated with the last SNP marker refers to its location in a contig that was not assigned to a chromosome prior to this study. Numbers to the left of the bar are distances in centimorgans. The red line indicates the LOD score for the likelihood that a QTL influencing grooming behavior is linked. The dotted line indicates the chromosome-wide empirical significance threshold of 0.05 as determined by 1000 permutations of phenotype data. Probe sequences matching the chromosome positions are available in <b><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0047269#pone.0047269.s001" target="_blank">Table S1</a></b>.</p

Candidate genes for honey bee mite-grooming behavior and their putative functions.

<p>Candidate genes for honey bee mite-grooming behavior and their putative functions.</p