TY  - JOUR
A1  - Nanda, Indrajit
A1  - Schories, Susanne
A1  - Simeonov, Ivan
A1  - Adolfi, Mateus Contar
A1  - Du, Kang
A1  - Steinlein, Claus
A1  - Alsheimer, Manfred
A1  - Haaf, Thomas
A1  - Schartl, Manfred
T1  - Evolution of the degenerated Y-chromosome of the swamp guppy, Micropoecilia picta
JF  - Cells
N2  - The conspicuous colour sexual dimorphism of guppies has made them paradigmatic study objects for sex-linked traits and sex chromosome evolution. Both the X- and Y-chromosomes of the common guppy (Poecilia reticulata) are genetically active and homomorphic, with a large homologous part and a small sex specific region. This feature is considered to emulate the initial stage of sex chromosome evolution. A similar situation has been documented in the related Endler’s and Oropuche guppies (P. wingei, P. obscura) indicating a common origin of the Y in this group. A recent molecular study in the swamp guppy (Micropoecilia. picta) reported a low SNP density on the Y, indicating Y-chromosome deterioration. We performed a series of cytological studies on M. picta to show that the Y-chromosome is quite small compared to the X and has accumulated a high content of heterochromatin. Furthermore, the Y-chromosome stands out in displaying CpG clusters around the centromeric region. These cytological findings evidently illustrate that the Y-chromosome in M. picta is indeed highly degenerated. Immunostaining for SYCP3 and MLH1 in pachytene meiocytes revealed that a substantial part of the Y remains associated with the X. A specific MLH1 hotspot site was persistently marked at the distal end of the associated XY structure. These results unveil a landmark of a recombining pseudoautosomal region on the otherwise strongly degenerated Y chromosome of M. picta. Hormone treatments of females revealed that, unexpectedly, no sexually antagonistic color gene is Y-linked in M. picta. All these differences to the Poecilia group of guppies indicate that the trajectories associated with the evolution of sex chromosomes are not in parallel.
KW  - sex chromosomes
KW  - heterochromatin
KW  - Y chromosome degeneration
KW  - meiosis
KW  - synaptonemal complex
KW  - recombination
KW  - 5-methylcytosine
KW  - testosterone
KW  - sexual antagonistic genes
KW  - sex linked pigmentation pattern
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-267242
SN  - 2073-4409
VL  - 11
IS  - 7
ER  - 
TY  - JOUR
A1  - Biscotti, Maria Assunta
A1  - Adolfi, Mateus Contar
A1  - Barucca, Marco
A1  - Forconi, Mariko
A1  - Pallavicini, Alberto
A1  - Gerdol, Marco
A1  - Canapa, Adriana
A1  - Schartl, Manfred
T1  - A comparative view on sex differentiation and gametogenesis genes in lungfish and coelacanths
JF  - Genome Biology and Evolution
N2  - Gonadal sex differentiation and reproduction are the keys to the perpetuation of favorable gene combinations and positively selected traits. In vertebrates, several gonad development features that differentiate tetrapods and fishes are likely to be, at least in part, related to the water-to-land transition. The collection of information from basal sarcopterygians, coelacanths, and lungfishes, is crucial to improve our understanding of the molecular evolution of pathways involved in reproductive functions, since these organisms are generally regarded as “living fossils” and as the direct ancestors of tetrapods. Here, we report for the first time the characterization of >50 genes related to sex differentiation and gametogenesis in Latimeria menadoensis and Protopterus annectens. Although the expression profiles of most genes is consistent with the intermediate position of basal sarcopterygians between actinopterygian fish and tetrapods, their phylogenetic placement and presence/absence patterns often reveal a closer affinity to the tetrapod orthologs. On the other hand, particular genes, for example, the male gonad factor gsdf (Gonadal Soma-Derived Factor), provide examples of ancestral traits shared with actinopterygians, which disappeared in the tetrapod lineage.
KW  - sex differentiation
KW  - Latimeria menadoensis
KW  - Protopterus annectens
KW  - evolution
KW  - testis
KW  - gametogenesis
KW  - ovary
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176774
VL  - 10
IS  - 6
ER  -