Sex Differences in Rhesus Monkeys’ Digit Ratio (2D:4D Ratio) and Its Association With Maternal Social Dominance Rank
Prenatal androgen exposure (PAE) plays a pivotal role in masculinizing the developing body and brain, and extreme exposure may contribute to autism, anxiety disorder and schizophrenia. One commonly used biomarker for PAE is the pointer-to-ring-finger digit length (2D:4D) ratio. Although this biomark...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2018-09-01
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| Series: | Frontiers in Behavioral Neuroscience |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fnbeh.2018.00213/full |
| _version_ | 1819228576051888128 |
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| author | Alexander Baxter Elizabeth K. Wood Parker Jarman Ashley N. Cameron John P. Capitanio John P. Capitanio J. Dee Higley |
| author_facet | Alexander Baxter Elizabeth K. Wood Parker Jarman Ashley N. Cameron John P. Capitanio John P. Capitanio J. Dee Higley |
| author_sort | Alexander Baxter |
| collection | DOAJ |
| description | Prenatal androgen exposure (PAE) plays a pivotal role in masculinizing the developing body and brain, and extreme exposure may contribute to autism, anxiety disorder and schizophrenia. One commonly used biomarker for PAE is the pointer-to-ring-finger digit length (2D:4D) ratio. Although this biomarker is widely used in human studies, relatively few studies have investigated 2D:4D ratio in nonhuman primates, particularly rhesus macaques (Macaca mulatta), one of the most commonly used animals in biomedical research. Thus far, data suggest that sexual dimorphism in 2D:4D ratio may be in the opposite direction in some monkey species, when compared to the pattern exhibited by humans and great apes. Using a large sample size, we investigated whether rhesus monkeys’ 2D:4D ratio shows the same sex-differentiated pattern present in other Old World monkey species. We also investigated whether individual differences in 2D:4D ratio are associated with the social dominance rank of subjects’ mothers during pregnancy, and the social dominance rank the subjects attained as adults. Subjects were 335 rhesus monkeys between 3 years and 24 years of age (M = 6.6). Maternal dominance rank during pregnancy and subjects’ adult dominance rank were categorized into tertiles (high, middle and low). Results showed that, across both hands, male rhesus monkeys exhibited higher 2D:4D ratio than females, a pattern consistent with other monkey species and a reversal from the pattern typically observed in humans and apes. This sex difference was modulated by maternal dominance rank, with female offspring of high-ranking and middle-ranking mothers exhibiting masculinized 2D:4D ratio, indicating that maternal dominance rank during pregnancy may influence levels of PAE. There was no association between subjects’ 2D:4D ratio and the social dominance rank they attained as adults. These findings show a consistent sex difference in Old World monkeys’ 2D:4D ratio that diverges from the pattern observed in apes and humans, and suggest maternal social dominance rank modulates PAE in rhesus monkeys. |
| first_indexed | 2024-12-23T10:59:28Z |
| format | Article |
| id | doaj.art-145159a273224dac9b4e0c948a356a82 |
| institution | Directory Open Access Journal |
| issn | 1662-5153 |
| language | English |
| last_indexed | 2024-12-23T10:59:28Z |
| publishDate | 2018-09-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Behavioral Neuroscience |
| spelling | doaj.art-145159a273224dac9b4e0c948a356a822022-12-21T17:49:40ZengFrontiers Media S.A.Frontiers in Behavioral Neuroscience1662-51532018-09-011210.3389/fnbeh.2018.00213383535Sex Differences in Rhesus Monkeys’ Digit Ratio (2D:4D Ratio) and Its Association With Maternal Social Dominance RankAlexander Baxter0Elizabeth K. Wood1Parker Jarman2Ashley N. Cameron3John P. Capitanio4John P. Capitanio5J. Dee Higley6Department of Psychology, Brigham Young University, Provo, UT, United StatesDepartment of Psychology, Brigham Young University, Provo, UT, United StatesDepartment of Psychology, Brigham Young University, Provo, UT, United StatesCalifornia National Primate Research Center (CNPRC), Davis, CA, United StatesCalifornia National Primate Research Center (CNPRC), Davis, CA, United StatesDepartment of Psychology, University of California, Davis, Davis, CA, United StatesDepartment of Psychology, Brigham Young University, Provo, UT, United StatesPrenatal androgen exposure (PAE) plays a pivotal role in masculinizing the developing body and brain, and extreme exposure may contribute to autism, anxiety disorder and schizophrenia. One commonly used biomarker for PAE is the pointer-to-ring-finger digit length (2D:4D) ratio. Although this biomarker is widely used in human studies, relatively few studies have investigated 2D:4D ratio in nonhuman primates, particularly rhesus macaques (Macaca mulatta), one of the most commonly used animals in biomedical research. Thus far, data suggest that sexual dimorphism in 2D:4D ratio may be in the opposite direction in some monkey species, when compared to the pattern exhibited by humans and great apes. Using a large sample size, we investigated whether rhesus monkeys’ 2D:4D ratio shows the same sex-differentiated pattern present in other Old World monkey species. We also investigated whether individual differences in 2D:4D ratio are associated with the social dominance rank of subjects’ mothers during pregnancy, and the social dominance rank the subjects attained as adults. Subjects were 335 rhesus monkeys between 3 years and 24 years of age (M = 6.6). Maternal dominance rank during pregnancy and subjects’ adult dominance rank were categorized into tertiles (high, middle and low). Results showed that, across both hands, male rhesus monkeys exhibited higher 2D:4D ratio than females, a pattern consistent with other monkey species and a reversal from the pattern typically observed in humans and apes. This sex difference was modulated by maternal dominance rank, with female offspring of high-ranking and middle-ranking mothers exhibiting masculinized 2D:4D ratio, indicating that maternal dominance rank during pregnancy may influence levels of PAE. There was no association between subjects’ 2D:4D ratio and the social dominance rank they attained as adults. These findings show a consistent sex difference in Old World monkeys’ 2D:4D ratio that diverges from the pattern observed in apes and humans, and suggest maternal social dominance rank modulates PAE in rhesus monkeys.https://www.frontiersin.org/article/10.3389/fnbeh.2018.00213/full2D:4D digit ratiosex differencesprenatal androgen exposurerhesus monkeysocial dominance rankmaternal androgens |
| spellingShingle | Alexander Baxter Elizabeth K. Wood Parker Jarman Ashley N. Cameron John P. Capitanio John P. Capitanio J. Dee Higley Sex Differences in Rhesus Monkeys’ Digit Ratio (2D:4D Ratio) and Its Association With Maternal Social Dominance Rank Frontiers in Behavioral Neuroscience 2D:4D digit ratio sex differences prenatal androgen exposure rhesus monkey social dominance rank maternal androgens |
| title | Sex Differences in Rhesus Monkeys’ Digit Ratio (2D:4D Ratio) and Its Association With Maternal Social Dominance Rank |
| title_full | Sex Differences in Rhesus Monkeys’ Digit Ratio (2D:4D Ratio) and Its Association With Maternal Social Dominance Rank |
| title_fullStr | Sex Differences in Rhesus Monkeys’ Digit Ratio (2D:4D Ratio) and Its Association With Maternal Social Dominance Rank |
| title_full_unstemmed | Sex Differences in Rhesus Monkeys’ Digit Ratio (2D:4D Ratio) and Its Association With Maternal Social Dominance Rank |
| title_short | Sex Differences in Rhesus Monkeys’ Digit Ratio (2D:4D Ratio) and Its Association With Maternal Social Dominance Rank |
| title_sort | sex differences in rhesus monkeys digit ratio 2d 4d ratio and its association with maternal social dominance rank |
| topic | 2D:4D digit ratio sex differences prenatal androgen exposure rhesus monkey social dominance rank maternal androgens |
| url | https://www.frontiersin.org/article/10.3389/fnbeh.2018.00213/full |
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