TY  - JOUR
A1  - Nanda, Indrajit
A1  - Schartl, Manfred
A1  - Epplen, Jörg T.
A1  - Feichtinger, Wolfgang
A1  - Schmid, Michael
T1  - Primitive sex chromosomes in poeciliid fishes harbor simple repetitive DNA sequences
N2  - The demonstration ofthe chromosomal mode ofsex determinationvia genetic experiments as well as the absence of heteromorphic sex chromosomes affirm poeciliid fishes as a unique group among vertebrates that are endowed with the mostprimitive form of sex chromosornes. In many different taxa the evolutionary process involved in the differentiation ofadvanced sex chromosomes is outlined through sex specifically organized repetitive sequences. In this investigation hydridization of synthetic probes specific to genomic simple repeat motifs uncovers a sex-specific hybridization pattern in certain viviparaus fishes ofthe family Poeciliidae. The hybridization pattern together with specific staining ofthe constitutive heterochromatin by C-banding reveals heterogamety in males (Poecilia reticulata) as weil as in females (P. sphenops). In P. velifera, however, C-banding alone fails to unravel the heterogametic status. The female specific W-chromosome can be detected by simple repetitive sequence probes. Therefore, the principal significance of heterochromatization as a means of generating differentiated sex chromosomes is evident.
KW  - Physiologische Chemie
Y1  - 1993
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61659
ER  - 
TY  - JOUR
A1  - Schartl, Manfred
A1  - Erbelding-Denk, Claudia
A1  - Holter, Sabine
A1  - Nanda, Indrajit
A1  - Schmid, Michael
A1  - Schroder, Johannes H.
A1  - Epplen, Jörg T.
T1  - Reproductive failure of dominant males in the poeciliid fish Limia perugiae determined by DNA fingerprinting
N2  - Hierarchical structures among male indlviduals in a population are frequently reflected ln differences in aggressive and reproductive behavior and access to the females. In general, sodal dominance requires the Investments, which in turn then may have to be compensated for by high reproductive success. However, this hypothesls has so far only been sufficiently tested in small mating groups (one or two males with one or two females) due to the difficulties of determining paternity by conventional methods. DNA fingerprinting overcomes these problems by offering the possibility to determine genetic relationships and mating patterns within larger groups [Borke, T. (1989) Trends Ecol. Evol. 4, 139-144]. We show here that in the poecUiid fish Limia perugitu, in small matlng groups the dominant male has 8 mating success of 100%, whereas ln larger groups lts contribution to the offspring unexpectedly drops to zero.
KW  - Physiologische Chemie
KW  - reproductive success
KW  - sexual selection
KW  - size polymorpbism
KW  - sodal domlnance
KW  - simple repetitive sequences
Y1  - 1993
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61643
ER  -