OB

[Patapon]

Sexual Conflict Resolved by Invasion of a Novel Sex Determiner in Lake Malawi
Cichlid Fishes
Reade B. Roberts, Jennifer R. Ser, Thomas D. Kocher*


Sex determination mechanisms differ among animal
species, but it is not clear how these differences evolve.
New sex determiners may arise in response to sexual
conflicts, which occur when traits benefit one sex but
hinder the other. Here we identified the genetic basis for
the orange-blotch (OB) color pattern, a trait under
sexually antagonistic selection in the cichlid fish of Lake
Malawi, East Africa. The OB phenotype is due to a cisregulatory
mutation in the Pax7 gene. OB provides
benefits of camouflage to females, but disrupts the
species-specific male color patterns used for mate
recognition. We suggest that the resulting sexual conflict
at OB has been resolved by selection for a novel female
sex determination locus, promoting its invasion into
populations with an ancestral male sex determination
system.


j'ai le pdf

[Romain]

Je veux bien s'il te plaît

[Kalao]

Pourrais-tu me l'envoyer aussi s'il te plaît?

J'imaginais bêtement que le caractère OB était forcément un handicap, rarissime dans le milieu naturel, en réalité c'est plus compliqué et plus intéressant que ça.

[Patapon]

il me faut ton mail....

[Aure67]

Je vais me mettre un peu a la lecture de tout cela, concernant le sujet de la coloration, il y a aussi : :read:

Assortative mating among Lake Malawi cichlid fish populations is
not simply predictable from male nuptial colour
Jonatan Blais†1,2,3, Martin Plenderleith†2, Ciro Rico3, Martin I Taylor4,
Ole Seehausen5,6, Cock van Oosterhout2 and George F Turner*

Surprisingly, laboratory mate choice experiments revealed significant assortative mating
not only between population pairs with differently coloured males, but between population pairs
with similarly-coloured males too. This suggested that assortative mating could be based on nonvisual
cues, so we further examined the sensory basis of assortative mating between two
populations with different male colour. Conducting trials under monochromatic (orange) light,
intended to mask the distinctive male dorsal fin hues (blue v orange) of these populations, did not
significantly affect the assortative mating by female P. emmiltos observed under control conditions.
By contrast, assortative mating broke down when direct contact between female and male was
prevented.
Conclusion: We suggest that non-visual cues, such as olfactory signals, may play an important role
in mate choice and behavioural isolation in these and perhaps other African cichlid fish. Future
speciation models aimed at explaining African cichlid radiations may therefore consider
incorporating such mating cues in mate choice scenarios


ou encore :

Reproductive isolation among deep-water cichlid fishes
of Lake Malawi differing in monochromatic male
breeding dress
MARTIN J. GENNER,*PAUL NICHOLS,*GARY R. CARVALHO,†ROSANNA L. ROBINSON,*PAUL W. SHAW‡and GEORGE F. TURNER

Abstract
Male nuptial colour hues are important for the maintenance of reproductive isolation among
cichlid fish species, and environmental changes that lead to narrower light spectra can lead
to hybridization. However, cichlid species can naturally co-occur in narrow light spectrum
habitats, such as turbid shallow lakes and the deep benthic zones of African rift lakes. Closely
related species from narrow light spectrum habitats tend to differ little in the palette of male
nuptial colours, thus for these taxa differences in colour patterns may be more important
than differences in colour hue for species recognition. To investigate this hypothesis we
examined morphometric and genetic differentiation among males of four sympatric putative
species within the deep-water genus
Diplotaxodon
. These taxa live in a narrow-light spectrum
environment where only blue light is present, and males differ primarily in ‘monochromatic’
black, white and silver patterning of the body and fins. Significant genetic differentiation was
present among taxa in both microsatellite DNA and mitochondrial DNA, including one pair
with no significant morphometric differentiation. Thus, these taxa represent reproductively
isolated biological species, a result consistent with male nuptial patterning being important
for species recognition and assortative mating. As such, we suggest that narrow-light
spectra need not always represent barriers to effective visually mediated mate recognition.