Tandem 6: Evolution of key life history events – the sex-specific link between fertility, pregnancy and longevity

Background - Natural selection still acts on contemporary humans in developed countries despite the benefits of hygiene, modern medicine and sufficient nutrition. In particular women are under selection for later menopause and older age at last child. This increase in reproductive lifespan has been interpreted as a response to the Western standard of living. Due to low early-life mortality current selection is thought to be primarily driven by variation in fertility. In addition, there is a growing number of studies that consistently show a positive correlation between the age at last birth and healthy longevity of the mother. Brothers of women who have children late also live longer, indicating a genetic component that could mediate its effects by postponing both sexual development and ageing. The genetic link between longevity and late-life fertility is supported by the observation that variation in three longevity genes also influences age at menopause or ovary reservoir. Egg production, pregnancy, and breast-feeding are united in human maternal investment. This prevents to determine how postponed maturation and late pregnancy affect longevity. Sex-role reversal is found in syngnathid fish (pipefish, seahorses), characterized by male pregnancy. In this case, the provisioning of eggs and parental investment are decoupled: the mother provides the eggs and the father the investment during pregnancy. Syngnathids are thus ideally suited for experimental validation of the observed correlations in humans.

Overall objectives

  • Investigate the correlation between late-life fertility/pregnancy and longevity in humans at the genetic and molecular level
  • Experimentally validate the causal relationship between sex-specific late life fertility/ pregnancy and longevity using a sex-role reversed pipefish
  • Assess genes with a function in key life history events (pregnancy, longevity) both in conventional and sex-role reversed species to assess homologous gene co-option in the convergent evolution of pregnancy in both females and males

Doctoral project 6.1: Late-life fertility and longevity in humans

Specific aims

  • Establish a list of genes and single nucleotide polymorphisms (SNPs) involved in fertility/pregnancy to be tested for an association with longevity
  • Identify novel longevity genes through a case-control association study in LLI and younger individuals by systematically analysing SNPs in the above candidate loci
  • Gain insights into mechanistic and functional processes (from genotype to phenotype) by performing in silico and possibly in vitro analyses of detected longevity-fertility genes and their associated SNPs

People working on this project

  • Prof. Dr. Almut Nebel
  • MSc Deepika Singhal

PI's Homepage: https://www.ikmb.uni-kiel.de/people/scientists/almut-nebel

Doctoral project 6.2: Pregnancy/late-life fertility and longevity in sex-role reversed pipefish

Specific aims

  • Experimentally analyse the late-life fertility/pregnancy and longevity trade-off in the sex-role reversed pipefish Syngnathus typhle
  • Experimentally evaluate sex-specific late-life fertility and longevity in the sex-role reversed pipefish Syngnathus typhle
  • Identify the molecular and functional basis of pregnancy, fertility and longevity in conventional and sex-role reversed lifestyle using transcriptomics and modifications of key pregnancy/fertility genes with CRISPR/cas9

People working on this project

  • Dr. Olivia Roth
  • MSc Freya Adele Hall Pappert

PI's Homepage: https://www.geomar.de/en/mitarbeiter/fb3/ev/oroth/