Repeated intraspecific divergence in life span and aging of African annual fishes along an aridity gradient

Abstract

Life span and aging are substantially modified by natural selection. Across species, higher extrinsic (environmentally related) mortality (and hence shorter life expectancy) selects for the evolution of more rapid aging. However, among populations within species, high extrinsic mortality can lead to extended life span and slower aging as a consequence of condition-dependent survival. Using within-species contrasts of eight natural populations of Nothobranchius fishes in common garden experiments, we demonstrate that populations originating from dry regions (with short life expectancy) had shorter intrinsic life spans and a greater increase in mortality with age, more pronounced cellular and physiological deterioration (oxidative damage, tumor load), and a faster decline in fertility than populations from wetter regions. This parallel intraspecific divergence in life span and aging was not associated with divergence in early life history (rapid growth, maturation) or pace-of-life syndrome (high metabolic rates, active behavior). Variability across four study species suggests that a combination of different aging and life-history traits conformed with or contradicted the predictions for each species. These findings demonstrate that variation in life span and functional decline among natural populations are linked, genetically underpinned, and can evolve relatively rapidly.

Maternal source of variability in the embryo development of an annual killifish

“…(), in that female age correlated positively with the duration of embryo development, our data also permit the alternative explanation that developmental trajectory involved a mechanism based on laying order sensu Martinez‐Ruiz & Garcia‐Roger (), rather than maternal chronological age. In the present study, all the eggs were collected within a period of 17 days, representing only approximately 12% of the reproductive lifespan in N. furzeri (Terzibasi et al ., ; Blažek et al ., ; but see also Valdesalici & Cellerino, ). In contrast, Podrabsky et al .…”

Community assembly inNothobranchiusannual fishes: Nested patterns, environmental niche and biogeographic history

“…Importantly, the altitudinal gradient in the study area coincides with a gradient of aridity where high‐altitude sites are significantly drier, with lower total rainfall, higher evapotranspiration rates, and lower predictability of rains (Terzibasi Tozzini et al., 2013; Vrtílek & Reichard, 2016b). The coastal plains are more humid, with temporary pools inundated for a longer period (Blažek et al., 2017; Terzibasi Tozzini et al., 2013). The flat topography of the coastal region likely connects isolated habitats with permanent water bodies more frequently than pools at a higher altitude.…”

“…Inappropriate conditions in the coastal region unlikely include a shorter duration of the dry period for embryo development, because N. furzeri and N. kadleci embryos can complete their development in less than a month (Blažek et al., 2013; Polačik, Blažek, & Reichard, 2016). Nevertheless, the more humid coastal region receives more seasonal and non‐seasonal rainfall (Blažek et al., 2017; Terzibasi Tozzini et al., 2013). It is possible that the eggs of N. furzeri and N. kadleci are more prone to non‐seasonal rains, triggering their hatching outside the appropriate season and compromising population persistence.…”

The African turquoise killifish: A research organism to study vertebrate aging and diapause

“…The turquoise killifish strain that is most frequently used is the GRZ strain, an inbred line that originates from a sample collected in 1970 in the Gona‐Re‐Zhou National Park of Zimbabwe (Parle, 1970). Since then, several additional samples have been collected in Mozambique and Zimbabwe, and wild strains or strains derived from these samples (e.g., the MZM0403 and 0410 strains which were collected in 2004) have also been broadly used for a variety of studies (Bartakova et al., 2013; Baumgart et al., 2016; Blazek et al., 2017; Kirschner et al., 2012; Reichard, Polacik & Sedlacek, 2009; Reichwald et al., 2015; Terzibasi et al., 2008; Valenzano et al., 2009, 2015). In particular, these strains were used to identify the genetic architecture underlying phenotypic differences in these strains, such as color (Valenzano et al., 2009) and survival under specific laboratory environments (Baumgart et al., 2016; Blazek et al., 2017; Reichwald et al., 2015; Valenzano et al., 2015).…”

“…In 2015, two independent groups de novo assembled and annotated the turquoise killifish genome: Anne Brunet's laboratory at Stanford University (African Turquoise Killifish Genome Browser: http://africanturquoisekillifishbrowser.org/; Valenzano et al., 2015) and Matthias Platzer's laboratory in Jena, Germany ( Nothobranchius furzeri Genome Browser: http://nfingb.leibniz-fli.de/; Reichwald et al., 2015). Additionally, other genomic resources have also been established through the years, including genetic linkage maps, quantitative trait loci, over 150 microsatellite markers (Blazek et al., 2017; Kirschner et al., 2012; Valenzano et al., 2009), and numerous transcriptomic and epigenomic datasets of different tissues at different ages using various strains (Baumgart et al., 2012, 2014, 2016, 2017; D'Angelo et al., 2014; Ng'oma, Groth, Ripa, Platzer & Cellerino, 2014; Petzold et al., 2013). A reference genome from the NCBI pipeline was made available online in 2016 (NCBI Genome ID: 2642, URL: https://www.ncbi.nlm.nih.gov/genome/2642).…”