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Fig. 1 | BMC Evolutionary Biology

Fig. 1

From: Phenotypic integration mediated by hormones: associations among digit ratios, body size and testosterone during tadpole development

Fig. 1

Proposed hypotheses for sexual dimorphism in 2D:4D ratios. a 2D:4D female-biased sexual dimorphism, which consists of larger digit ratios in females (F) than males (M), a pattern explained by Digit IV responding to sex-steroids (‘SS’, androgens and estrogens); (b and c) two hypotheses proposed here for the establishment of male-biased 2D:4D digit ratios. b Hypothesis I (HI): male-biased patterns are explained by inverted between-sex responses of Digit IV to sex-steroids; thus, Digit IV becomes shorter in males in response to testosterone. c Hypothesis II (HII): male-biased patterns reflect a change in the identity of the digit responding to sex-steroids, not the direction of the response (elongation or shortening); thus, Digit II is the one dimorphic and is longer in males and shorter in females

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BMC Ecology and Evolution

ISSN: 2730-7182

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