Heritability of Directional Asymmetry inDrosophila melanogaster

Abstract

Directional asymmetry (DA), the consistent difference between a pair of morphological structures in which the same side is always larger than the other, presents an evolutionary mystery. Although many paired traits show DA, genetic variation for DA has not been unambiguously demonstrated. Artificial selection is a powerful technique for uncovering selectable genetic variation; we review and critique the limited number of previous studies that have been performed to select on DA and present the results of a novel artificial selection experiment on the DA of posterior crossvein location in Drosophila wings. Fifteen generations of selection in two genetically distinct lines were performed and none of the lines showed a significant response to selection. Our results therefore support and reconfirm previous findings; despite apparent natural variation and evolution of DA in nature, DA remains a paradoxical trait that does not respond to artificial selection.

Influence of Inbreeding on Female Mate Choice in Two Species of Drosophila

“…The computer overlaid a spline onto the image in order to calculate the distances between intersections of the veins in the wings. This data has been used successfully to quantitatively describe the size and shape of Drosophila wings (Carter et al 2009a, b; Carter and Houle 2011; Pelabon et al 2010). …”

Asimetría cráneo-mandibular de Artibeus lituratus (Chiroptera, Phyllostomidae) en Colombia

“…La Asimetría Direccional (AD) es un tipo de asimetría en la que todos los individuos dentro de una población mantienen un patrón de asimetría constante. Esta asimetría ha sido caracterizada como un tipo de asimetría natural propia de la biología de la población, la cual puede derivarse tanto de la herencia genética, como de la importancia funcional que adquieran ciertos rasgos con respecto al ambiente en el que se desarrollen (Carter et al 2009). …”

“…La antisimetría (AA) se considera la variación aleatoria del plan de simetría entre los individuos de una población (Graham et al 2010); su interpretación biológica ha sido debatida, ya que se le han atribuido tanto características hereditarias (Graham et al 1993b) como de respuesta al estrés (Carter et al 2009). …”

Heritabilities of Directional Asymmetry in the Fore- and Hindlimbs of Rabbit Fetuses

“…A case in point is represented by morphological and behavioural lateralization (e.g., [1]). Although the external metazoan body plan is assumed to be symmetric, many cases of consistent differences between a pair of morphological structures have been reported (called directional asymmetry, abbreviated as DA; e.g., [2]). Some are very conspicuous, such as the morphology of flounders, spiraled snails or the ears of owls.…”

“…In a recent review of DA in insect wing size, Pélabon and Hansen [5] concluded that the small magnitude and imprecise expression of DA in insect wings precludes it from playing a major adaptive role. In addition, in spite of relatively few studies, the heritability of DA in insect wing size (studied in Drosophila melanogaster ) appears very low at best ([2]; Table 1). In contrast, in vertebrates, where the genetic basis of DA has been mainly studied in humans and in mice mandibles, moderate to high levels of genetic variation have been demonstrated (Table 1).…”