The ratio of the second-to-fourth finger lengths (2D:4D) has been proposed as an indicator of prenatal sex differentiation. However, 2D:4D has not been studied in the closest living human relatives, chimpanzees (Pan troglodytes) and bonobos (Pan paniscus). We report the results from 79 chimpanzees and 39 bonobos of both sexes, including infants, juveniles, and adults. We observed the expected sex difference in 2D:4D, and substantially higher, more human-like, 2D:4D in bonobos than chimpanzees. Previous research indicates that sex differences in 2D:4D result from differences in prenatal sex hormone levels. We hypothesize that the species difference in 2D:4D between bonobos and chimpanzees suggests a possible role for early exposure to sex hormones in the development of behavioral differences between the two species.
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http://dx.doi.org/10.1016/j.jhevol.2008.12.004 | DOI Listing |
Sci Rep
November 2024
Department of Anthropology, Faculty of Biology and Environmental Protection, University of Łódź, Łódź, Poland.
The study aimed to analyse the association between the digit ratio in adult women and the degree of air pollution (suspended particulate matter, sulphur dioxide, nitric dioxide, benzene levels) in the place of residence of their mothers during pregnancy. The data was collected from female students in several Polish cities. Measurements were taken, and questionnaire data were collected.
View Article and Find Full Text PDFInt J Clin Pediatr Dent
June 2024
Department of Pediatric and Preventive Dentistry, Dental College and Hospital, Bharati Vidyapeeth (Deemed to be University), Pune, Maharashtra, India.
Background: Genetic predilection toward sweeter cariogenic foods mediated by the gene, tested by phenylthiourea [phenylthiocarbamide (PTC)] compounds. Some individuals find it extremely bitter whereas some find it completely tasteless, being classified as a taster and a nontaster respectively. A majority of nontasters prefer foods with sweeter and stronger flavors, thus making them more susceptible to dental caries.
View Article and Find Full Text PDFAm J Hum Biol
November 2024
Department of Anthropology, Istanbul University, Istanbul, Turkey.
Objective: Human sexual dimorphism in physical strength manifests itself in men having a greater muscle mass than women, reflecting ancestral roles in competition, protection, and provisioning. Prenatal testosterone exposure, approximated via the second-to-fourth digit ratio (2D:4D), is linked to increased muscular strength in both sexes, indicating a developmental influence. Previous research has shown that both physical strength and 2D:4D have facial shape correlates, especially in men, but most studies have focused on Western populations and one trait.
View Article and Find Full Text PDFAm J Hum Biol
November 2024
Department of Anthropology, Faculty of Biology and Environmental Protection, University of Łódź, Łódź, Poland.
Objectives: Second to fourth digit ratio is widely known indicator of prenatal sex hormones proportion. Higher prenatal androgenization results in longer fourth finger and lower 2D:4D index. The aim of this study was to determine whether the 2D:4D digit ratio is associated with DNA methylation (DNAm) age dependently on sex.
View Article and Find Full Text PDFCancer Epidemiol
October 2024
Epidemiology and Biostatistics Unit, Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique, Université du Québec, Laval, QC, Canada; Department of Social and Preventive Medicine, School of Public Health, Université de Montréal, Montréal, QC, Canada. Electronic address:
Background: The second-to-fourth digit ratio (2D:4D) is thought to reflect prenatal exposure to sex steroids. We investigated the relationship between 2D:4D and odds of prostate cancer.
Method: Data were collected in PROtEuS, a population-based case-control study conducted in Montréal, Canada (2005-2012), including 1931 incident prostate cancer cases aged < 76 years and 1994 population controls.
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