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  - Schartl, Manfred
A1  - Walter, Ronald B.
A1  - Shen, Yingjia
A1  - Garcia, Tzintzuni
A1  - Catchen, Julian
A1  - Amores, Angel
A1  - Braasch, Ingo
A1  - Chalopin, Domitille
A1  - Volff, Jean-Nicolas
A1  - Lesch, Klaus-Peter
A1  - Bisazza, Angelo
A1  - Minx, Pat
A1  - Hillier, LaDeana
A1  - Wilson, Richard K.
A1  - Fürstenberg, Susan
A1  - Boore, Jeffrey
A1  - Searle, Steve
A1  - Postlethwait, John H.
A1  - Warren, Wesley C.
T1  - The genome of the platyfish, Xiphophorus maculatus, provides insights into evolutionary adaptation and several complex traits
JF  - Nature Genetics
N2  - Several attributes intuitively considered to be typical mammalian features, such as complex behavior, live birth and malignant disease such as cancer, also appeared several times independently in lower vertebrates. The genetic mechanisms underlying the evolution of these elaborate traits are poorly understood. The platyfish, X. maculatus, offers a unique model to better understand the molecular biology of such traits. We report here the sequencing of the platyfish genome. Integrating genome assembly with extensive genetic maps identified an unexpected evolutionary stability of chromosomes in fish, in contrast to in mammals. Genes associated with viviparity show signatures of positive selection, identifying new putative functional domains and rare cases of parallel evolution. We also find that genes implicated in cognition show an unexpectedly high rate of duplicate gene retention after the teleost genome duplication event, suggesting a hypothesis for the evolution of the behavioral complexity in fish, which exceeds that found in amphibians and reptiles.
KW  - genomics
KW  - genomic analysis
KW  - evolutionary biology
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-132152
VL  - 45
IS  - 5
ER  -