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Is preterm birth a human-specific syndrome?

Phillips JB, Abbot P, Rokas A - Evol Med Public Health (2015)

Bottom Line: Within species, gestation length is normally distributed, and all species appear to occasionally give birth before the 'optimal' time.Furthermore, human gestation length, like that of many mammalian species, scales proportionally to body mass, suggesting that this trait, like many others, is constrained by body size.Describing PTB broadly in mammals opens avenues for comparative studies on the physiological and genetic regulators of birth timing as well as the development of new mammalian models of the disease.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Vanderbilt University, VU Station B 35-1364, Nashville, TN 37235, USA.

No MeSH data available.


Related in: MedlinePlus

Gestation length is constrained by maternal body mass in placental mammals. Logarithmic plot of gestation length (days) against maternal body mass (grams) for 1100 placental mammals (A) and 120 primates (B). The scaling coefficient for all mammals is 0.09 (SE = 0.007). Altricial and precocial mammals have similar slopes, 0.10 (SE = 0.008) and 0.10 (SE = 0.01), respectively. Within primates, the scaling coefficient is 0.08 (SE = 0.02). Epitheliochorial and hemochorial have similar slopes, 0.10 (SE = 0.04) and 0.09 (SE = 0.02), respectively. Mass and gestation length data taken from the PanTheria database [133]. Offspring number per litter was used as a proxy for neonate development state. Placental structure was as described by Mossman [134]. Data were linked to a supertree of extant mammals [135]. We present the relationship between log-transformed body mass, and log-transformed gestation length using phylogenetic generalized least squares. Statistical tests were performed in R 3.1.2 [123] using the packages ape [136], caper [137] and nlme [138]
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eov010-F2: Gestation length is constrained by maternal body mass in placental mammals. Logarithmic plot of gestation length (days) against maternal body mass (grams) for 1100 placental mammals (A) and 120 primates (B). The scaling coefficient for all mammals is 0.09 (SE = 0.007). Altricial and precocial mammals have similar slopes, 0.10 (SE = 0.008) and 0.10 (SE = 0.01), respectively. Within primates, the scaling coefficient is 0.08 (SE = 0.02). Epitheliochorial and hemochorial have similar slopes, 0.10 (SE = 0.04) and 0.09 (SE = 0.02), respectively. Mass and gestation length data taken from the PanTheria database [133]. Offspring number per litter was used as a proxy for neonate development state. Placental structure was as described by Mossman [134]. Data were linked to a supertree of extant mammals [135]. We present the relationship between log-transformed body mass, and log-transformed gestation length using phylogenetic generalized least squares. Statistical tests were performed in R 3.1.2 [123] using the packages ape [136], caper [137] and nlme [138]

Mentions: Allometric relationships have also been described for many mammalian reproductive traits, such as litter weight [38, 43, 44], neonate weight [38, 43–45], neonate brain weight [42, 43, 46] and the per capita growth rate (Malthusian parameter) [38, 45], providing a window for understanding the evolution of pregnancy-associated traits in mammalian species and the identification of trends and constraints. For example, study of the relationship between neonatal brain mass and body size has identified an evolutionary trend toward larger brain size relative to fetal body mass compared to non-primates [42]. Gestation length has also been found to scale to maternal body mass by 1/4 [38, 43, 47, 48], but subsequent studies utilizing phylogeny-informed statistics support a scaling exponent closer to 0.10 [49, 50] (Fig. 2). The relationship between body mass and gestation length suggests that the timing of gestation in mammals is either constrained by maternal body mass, or that the two traits are under a shared constraint. For example, recent work has suggested that human gestation length may be primarily constrained by metabolism [51], raising the alternative hypothesis that gestation length and maternal body mass, which also allometrically scales with metabolism, may be under a shared metabolic constraint.Figure 2.


Is preterm birth a human-specific syndrome?

Phillips JB, Abbot P, Rokas A - Evol Med Public Health (2015)

Gestation length is constrained by maternal body mass in placental mammals. Logarithmic plot of gestation length (days) against maternal body mass (grams) for 1100 placental mammals (A) and 120 primates (B). The scaling coefficient for all mammals is 0.09 (SE = 0.007). Altricial and precocial mammals have similar slopes, 0.10 (SE = 0.008) and 0.10 (SE = 0.01), respectively. Within primates, the scaling coefficient is 0.08 (SE = 0.02). Epitheliochorial and hemochorial have similar slopes, 0.10 (SE = 0.04) and 0.09 (SE = 0.02), respectively. Mass and gestation length data taken from the PanTheria database [133]. Offspring number per litter was used as a proxy for neonate development state. Placental structure was as described by Mossman [134]. Data were linked to a supertree of extant mammals [135]. We present the relationship between log-transformed body mass, and log-transformed gestation length using phylogenetic generalized least squares. Statistical tests were performed in R 3.1.2 [123] using the packages ape [136], caper [137] and nlme [138]
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493222&req=5

eov010-F2: Gestation length is constrained by maternal body mass in placental mammals. Logarithmic plot of gestation length (days) against maternal body mass (grams) for 1100 placental mammals (A) and 120 primates (B). The scaling coefficient for all mammals is 0.09 (SE = 0.007). Altricial and precocial mammals have similar slopes, 0.10 (SE = 0.008) and 0.10 (SE = 0.01), respectively. Within primates, the scaling coefficient is 0.08 (SE = 0.02). Epitheliochorial and hemochorial have similar slopes, 0.10 (SE = 0.04) and 0.09 (SE = 0.02), respectively. Mass and gestation length data taken from the PanTheria database [133]. Offspring number per litter was used as a proxy for neonate development state. Placental structure was as described by Mossman [134]. Data were linked to a supertree of extant mammals [135]. We present the relationship between log-transformed body mass, and log-transformed gestation length using phylogenetic generalized least squares. Statistical tests were performed in R 3.1.2 [123] using the packages ape [136], caper [137] and nlme [138]
Mentions: Allometric relationships have also been described for many mammalian reproductive traits, such as litter weight [38, 43, 44], neonate weight [38, 43–45], neonate brain weight [42, 43, 46] and the per capita growth rate (Malthusian parameter) [38, 45], providing a window for understanding the evolution of pregnancy-associated traits in mammalian species and the identification of trends and constraints. For example, study of the relationship between neonatal brain mass and body size has identified an evolutionary trend toward larger brain size relative to fetal body mass compared to non-primates [42]. Gestation length has also been found to scale to maternal body mass by 1/4 [38, 43, 47, 48], but subsequent studies utilizing phylogeny-informed statistics support a scaling exponent closer to 0.10 [49, 50] (Fig. 2). The relationship between body mass and gestation length suggests that the timing of gestation in mammals is either constrained by maternal body mass, or that the two traits are under a shared constraint. For example, recent work has suggested that human gestation length may be primarily constrained by metabolism [51], raising the alternative hypothesis that gestation length and maternal body mass, which also allometrically scales with metabolism, may be under a shared metabolic constraint.Figure 2.

Bottom Line: Within species, gestation length is normally distributed, and all species appear to occasionally give birth before the 'optimal' time.Furthermore, human gestation length, like that of many mammalian species, scales proportionally to body mass, suggesting that this trait, like many others, is constrained by body size.Describing PTB broadly in mammals opens avenues for comparative studies on the physiological and genetic regulators of birth timing as well as the development of new mammalian models of the disease.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Vanderbilt University, VU Station B 35-1364, Nashville, TN 37235, USA.

No MeSH data available.


Related in: MedlinePlus