Cross-species chromosome painting in bats from Madagascar: the contribution of Myzopodidae to revealing ancestral syntenies in Chiroptera

Abstract

The chiropteran fauna of Madagascar comprises eight of the 19 recognized families of bats, including the endemic Myzopodidae. While recent systematic studies of Malagasy bats have contributed to our understanding of the morphological and genetic diversity of the island's fauna, little is known about their cytosystematics. Here we investigate karyotypic relationships among four species, representing four families of Chiroptera endemic to the Malagasy region using cross-species chromosome painting with painting probes of Myotis myotis: Myzopodidae (Myzopoda aurita, 2n = 26), Molossidae (Mormopterus jugularis, 2n = 48), Miniopteridae (Miniopterus griveaudi, 2n = 46), and Vespertilionidae (Myotis goudoti, 2n = 44). This study represents the first time a member of the family Myzopodidae has been investigated using chromosome painting. Painting probes of M. myotis were used to delimit 29, 24, 23, and 22 homologous chromosomal segments in the genomes of M. aurita, M. jugularis, M. griveaudi, and M. goudoti, respectively. Comparison of GTG-banded homologous chromosomes/chromosomal segments among the four species revealed the genome of M. aurita has been structured through 14 fusions of chromosomes and chromosomal segments of M. myotis chromosomes leading to a karyotype consisting solely of bi-armed chromosomes. In addition, chromosome painting revealed a novel X-autosome translocation in M. aurita. Comparison of our results with published chromosome maps provided further evidence for karyotypic conservatism within the genera Mormopterus, Miniopterus, and Myotis. Mapping of chromosomal rearrangements onto a molecular consensus phylogeny revealed ancestral syntenies shared between Myzopoda and other bat species of the infraorders Pteropodiformes and Vespertilioniformes. Our study provides further evidence for the involvement of Robertsonian (Rb) translocations and fusions/fissions in chromosomal evolution within Chiroptera.

Chromosome Evolution in Bats as Revealed by FISH: The Ongoing Search for the Ancestral Chiropteran Karyotype

“…This fission separates the HSA16 homologous segment from the HSA7-5 homologous segment, as has been shown for Hipposideros larvatus [Volleth et al, 2002]. Fission of the MMY8 homolog has also been found in Myzopoda [Richards et al, 2010]. Painting with human probes is needed to clarify whether the breakpoint in Myzopoda is similar to that in Rhinolophoidea.…”

“…Only these chromosomal features that have been found in more than 1 taxon up to date are presented in table 5 (numbers 1-19). Closer examination and recent results revealed that some characters, which have been previously reported to be shared features [Volleth et al, 2002;Mao et al, 2008;Richards et al, 2010], represent in fact 2 different characters (numbers 20-23). Therefore, we separated these features into 'a' and 'b' in table 5 .…”

“…An impressive example is the phyllostomid genus Carollia ( C. brevicauda 2n = 21; FISH results by Pieczarka et al [2005]). Another example is the Malagasy bat Myzopoda aurita (MAU), for which tandem fusions have been proposed to explain the formation of chromosomes MAU4 and MAU5 [Richards et al, 2010].…”

“…Chromosomal characters derived from FISH analyses have been used to investigate evolutionary relationships at various taxonomic levels within Chiroptera [Volleth et al, 2002;Mao et al, 2007Mao et al, , 2008Richards et al, 2010]. An overview of published data is given in table 5 .…”

“…Due to the large number of convergent events, phylogenetic analysis of chromosomal characters to resolve interfamily relationships using parsimony resulted in numerous parsimonious trees with poor resolution [Mao et al, 2008]. Therefore, cytogenetic features have been mapped onto the molecular consensus tree [Eick et al, 2005;Teeling et al, 2005] in recent analyses [Mao et al, 2008;Richards et al, 2010]. FISH results for species in additional bat families (e.g.…”