Meiotic analyses of the sex chromosomes in Carolliinae-Phyllostomidae (Chiroptera): NOR separates the XY₁Y₂ into two independent parts

Abstract

Meiotic analyses of the sex chromosomes were made in two different species belonging to the subfamily Carollinae (Phyllostomidae, Chiroptera): Rhinophylla pumilio and Carollia perspicillata. These species have different sex chromosome systems. Through banding techniques, chromosomes homologies between Carollia perspicillata and Rhinophylla pumilio were not found, possibly because Carollia species have highly rearranged chromosomes. Probably, Rhinophylla is better associated to Phyllostomini tribe. Sex vesicle pairing behavior at the meiotic prophase was analyzed in both species. R. pumilio had a simple sex chromosome system (XX/XY), the XY pair showed an asynchronic behavior compared to the autosomal bivalents. The sex vesicle showes the X and Y pairing in the pseudoautosomal region. Moreover, a folding of the X-asynaptic axis on itself and condensed differentiated axes were also identified. In C. perspicillata, with a multiple sex chromosome system (XY 1 Y 2), the segments Xp-Y 1 and Xq-Y 2 paired independently from each other. Compared to the autosomes, the sex vesicle showed a precocious pairing behavior. In C. perspicillata, a NOR stained with silver was localized in the X rearranged chromosome. Possibly, this region separates the XY 1 Y 2 trivalent in two independent parts: one involving the X and Y 2 autosomal with transcriptional activity, and the other corresponding to the original X and Y sex pair.

Neo-XY body: an analysis of XY₁Y₂ meiotic behavior in <i>Carollia</i> (Chiroptera, Phyllostomidae) by chromosome painting

“…Figure 5 shows the evolution of the sex chromosomes with the pairing of the Y 2 with the Xq-A (yellow), suggesting the fusion of the autosome (A) to the Xq in C. perspicillata . Previously we pos- tulated an Xq-A translocation in C. perspicillata (Noronha et al, 2004), but our new data do not corroborate that. Solari and Pigozzi (1994) analyzed the meiotic behavior of the sex chromosome trivalent in Artibeus lituratus.…”

“…The FISH analyses revealed a characteristic behavior of the XY 1 Y 2 in pachytene, previously named the sex vesicle or sex body (Solari and Pigozzi, 1994;Noronha et al, 2004). In this work we define it as the neo-XY body, since the autosomal segment is not compacted as it should be in a sex body.…”

“…In C. perspicillata , instead of heterochromatin, it seems that the nucleolar organizing region (NOR) blocks the spreading of X inactivation to the autosomal region (Noronha et al, 2004). According to Handel (2004), the XY body formation is under regulation, controlled intrinsically and autonomously in male germ cells.…”

“…Hsu et al (1968) described the diplotene phase in Carollia perspicillata and observed the formation of a sex trivalent (XY 1 Y 2 ), pointing out the pairing of the homologous region between Xq and Y 2 . Noronha et al (2004) applied the conventional technique for meiotic analysis to C. perspicillata and suggested the formation of a typical sex vesicle (SV) in pachytene. From the more advanced phases on, such as diplotene and diakinesis, the sex trivalent (XY 1 Y 2 ) presented differences in the behavior of the original XY axes as compared to the translocated autosome.…”

Chromosome Analysis and Morphometric of Intermediate Roundleaf Bat, Hipposideros larvatus (Chiroptera, Hipposideridae) by Conventional, GTG-banding and Ag-NOR Banding Techniques

“…The objective of this technique is to detect NORs which represent the location of genes that function in ribosome synthesis. The location of NORs in several bats has been analyzed using the Ag-NOR banding technique (Volleth 1987, Morielle-Verielle and VarellaGarcia 1988, Souza and Araújo 1990, Morielle-Verielle et al 1992, Rodrigues et al 2000, 2003, Santos et al 2002, Noronha et al 2004, Faria et al 2009, Garcia and Pessôa 2010, Vilamiu et al 2010, Gomes et al 2012. Eukaryote ribosomal RNA genes are organized into two different gene families: a major one encoding 18S, 5.8S and 28S rRNAs, and a small one encoding 5S rRNA.…”