So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Human biochemical genetics

The relationship between morphometrics and phylogenetic analysis has long been controversial. Here we propose an approach that is based on mapping morphometric traits onto phylogenies derived from other data and thus avoids the pitfalls encountered by previous studies. This method treats shape as a single, multidimensional character. We propose a test for the presence of a phylogenetic signal in morphometric data, which simulates the null hypothesis of the complete absence of phylogenetic structure by permutation of the shape data among the terminal taxa. We also propose 2 measures of the fit of morphometric data to the phylogeny that are direct extensions of the consistency index and retention index used in traditional cladistics. We apply these methods to a small study of the evolution of wing shape in the Drosophila melanogaster subgroup, for which a very strongly supported phylogeny is available. This case study reveals a significant phylogenetic signal and a relatively low degree of homoplasy. Despite the low homoplasy, the shortest tree computed from landmark data on wing shape is inconsistent with the well-supported phylogenetic tree from molecular data, underscoring that morphometric data may not provide reliable information for inferring phylogeny.

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Testing and Quantifying Phylogenetic Signals and Homoplasy in Morphometric Data

Europe harbours several endemic honeybee (Apis mellifera) subspecies. Yet the distribution of these subspecies is nowadays also much influenced by beekeeping activities. Large scale migratory beekeeping and trade in queens, coupled with the promiscuous mating system of honeybees, have exposed native European honeybees to increasing introgressive hybridization with managed non-native subspecies, which may lead to the loss of valuable combinations of traits shaped by natural selection. Other threats to European honeybees are factors that have caused a progressive decline in A. mellifera throughout the world in recent years, leading to large economic losses and jeopardizing ecosystem functioning. We review the biodiversity of European honeybees and summarize the management and conservation strategies employed by different countries. A comprehensive picture of the beekeeping industry in Europe is also provided. Finally we evaluate the potential threats affecting the biodiversity of European honeybee populations and provide some perspectives for future research.

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Biodiversity, conservation and current threats to European honeybees*

SummaryThe natural diversity of honey bees in Europe is eroding fast. A multitude of reasons lead to a loss of both genetic diversity and specific adaptations to local conditions. To preserve locally adapted bees through breeding efforts and to maintain regional strains in conservation areas, these valuable populations need to be identified.In this paper, we give an overview of methods that are currently available and used for recognition of honey bee subspecies and ecotypes, or that can be utilised to verify the genetic origin of colonies for breeding purposes. Beyond summarising details of morphometric, allozyme and DNA methods currently in use, we report recommendations with regard to strategies for sampling, and suggest methods for statistical data analysis. In particular, we emphasise the importance of reference data and consistency of methods between laboratories to yield comparable results.

Standard methods for characterising subspecies and ecotypes of Apis mellifera

Currently available morphometric and genetic techniques that can accurately identify African- ized honey bees are both costly and time consuming. We tested two new morphometric techniques (ABIS - Automatic Bee Identification System and geometric morphometrics analysis) on samples consisting of digital images of five worker forewings per colony. These were collected from 394 colonies of Africanized bees from all over Brazil and from colonies of African bees, Apis mellifera scutellata (n = 14), and Euro- pean bees, A. m. ligustica (n = 10), A. m. mellifera (n = 15), and A. m. carnica (n=15) from the Ruttner collection in Oberursel, Germany (preserved specimens). Both methods required less than five minutes per sample, giving more than 99% correct identifications. There was just one misidentification (based on ge- ometric morphometrics analysis) of Africanized bees compared with European subspecies, which would be the principal concern in newly-colonized areas, such as the southern USA. These new techniques are inexpensive, fast and precise. Africanized honey bee / morphometrics / geometric morphometrics analysis / ABIS / Apis mellifera / automatic identification

/pdf/identification-of-africanized-honey-bees-through-wing-1oiyfo96fp.pdf

Identification of Africanized honey bees through wing morphometrics: two fast and efficient procedures

La morphometrie a joue depuis longtemps un role important dans les etudes de taxonomie. Lorsqu'elle est couplee aux statistiques multivariees, c'est un outil tres puissant pour les analyses discriminantes et donc-pour l'identification des especes. Chez Apis mellifera de nombreuses differences entre sous-especes sont quantitatives et les diverses etudes menees jusqu'a present ont toujours utilise les mesures de diverses parties du corps de l'abeille. Afin de simplifier et d'accelerer les analyses, nous avons mesure 11 caracteristiques d'une seule cellule de l'aile anterieure pour savoir si les differences dans cette cellule permettaient de discriminer les trois sous-especes A. mellifera ligustica, A. m. camica et les abeilles africanisees du Bresil. Une analyse en composantes principales a ete effectuee sur les mesures afin de determiner si notre corpus de donnees formait trois groupements distincts (Fig. 3). Ceux-ci ont ete verifies par une analyse discriminante (Fig. 4). Les caracteristiques retenues forment bien trois groupes significativement differents (P < 0,00001) et la fonction discriminative lineaire a pu classer correctement 98,7 % des echantillons. Ces resultats montrent que des mesures d'une petite partie du corps de l'abeille sont suffisantes pour discriminer les sous-especes.

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Morphometric differences in a single wing cell can discriminate Apis mellifera racial types

The Drosophila buzzatii species cluster consists of the sibling species D. buzzatii, D. koepferae, D. serido, D. borborema, D. seriema, D. antonietae and D. gouveai, all of which breed exclusively in decaying cactus tissue and, except for D. buzzatii (a colonizing subcosmopolitan species), are endemic to South America. Using a morphometric approach and multivariate analysis of 17 wing parameters, we investigated the degree of divergence in wing morphology among the sibling species of this cluster. Significant differences were obtained among the species and discriminant analysis showed that wing morphology was sufficiently different to allow the correct classification of 98.6% of the 70 individuals analysed. The phenetic relationships among the species inferred from UPGMA cluster analysis based on squared Mahalanobis distances (D2) were generally compatible with previously published phylogenetic relationships. These results suggest that wing morphology within D. buzzatii cluster is of phylogenetic importance.

Zusammenfassung

Das Artencluster Drosophila buzzatii umfasst die nahe verwandten Arten D. buzzatii, D. koepferae, D. serido, D. borborema, D. seriema, D. antonietae und D. gouveai. All diese Arten pflanzen sich ausschliesslich auf verfaulendem Kaktusgewebe fort. Mit Ausnahme von D. buzzatii (einer kolonisierenden subkosmopolitischen Art) sind alle diese Arten endemisch fur Sudamerika. In einem morphometrischen Ansatz und mittels multivariater Analyse von 17 Flugelparametern untersuchten wir die Flugelmorphologie dieses Artenclusters im Hinblick auf Divergenzen. Die einzelnen Arten weichen signifikant voneinander ab, so dass es moglich war, 98,6% von 70 untersuchten Tieren mittels dieser Unterschiede in der Flugelmorphologie korrekt zu klassifizieren. Die phenetischen Beziehungen zwischen den Arten, die mittels UPGMA-Clusteranalyse basierend auf dem Quadrat der Mahalanobis-Distanzen (D2) ermittelt wurden, stimmten im allgemeinen mit den bereits publizierten phylogenetischen Beziehungen uberein. Die Ergebnisse lassen den Schluss zu, dass die Flugelmorphologie ein wichtiges phylogenetisches Merkmal fur das D. buzzatii Artencluster sind.

Divergence in wing morphology among sibling species of the Drosophila buzzatii cluster

Drosophila serido and D. antonietae are sibling species belonging to the Drosophila buzzatii cluster. Morphologically, they can only be discriminated by quantitative traits. In this paper we analyze the length and equalized average curvature of four regions of the aedeagus of D. antonietae and D. serido. Specimens of D. serido and D. antonietae were classified correctly 96.74% of the time. Based only on the variable that most contributed to the discrimination of the groups (equalized average curvature of the arch IV of the aedeagus), we observed significant intraspecific morphological divergence in D. serido in relation to the D. antonietae, in agreement with other markers. The high morphological divergence in equalized average curvature of the arch IV of the aedeagus shows that this region evolved faster than others, since the divergence of the two species. The importance of the present study to the understanding of the genetic basis that controls the formation of the aedeagus, in the species of the Drosophila buzzatii cluster, is discussed.

/pdf/aedeagus-morphology-as-a-discriminant-marker-in-two-closely-15sy9wednl.pdf

Pedro Roberto Rodrigues Prado

Papers

Morphometric differences in a single wing cell can discriminate Apis mellifera racial types

Divergence in wing morphology among sibling species of the Drosophila buzzatii cluster

Aedeagus morphology as a discriminant marker in two closely related Cactophilic species of Drosophila (Diptera; Drosophilidae) in South America

Analysis of sound components of sexual courtship of two subspecies of Drosophila mercatorum (Diptera, Drosophilidae)

Curvature measurement as a tool for the analysis of morphometric variation using Drosophila wings as a model