Diversity in the Toll-Like Receptor Genes of the African Penguin (Spheniscus demersus)

The African penguin, Spheniscus demersus, is listed as Endangered by the IUCN Red List
of Threatened Species due to the drastic reduction in population numbers over the last 20
years. To date, the only studies on immunogenetic variation in penguins have been conducted on the major histocompatibility complex (MHC) genes. It was shown in humans that
up to half of the genetic variability in immune responses to pathogens are located in nonMHC genes. Toll-like receptors (TLRs) are now increasingly being studied in a variety of
taxa as a broader approach to determine functional genetic diversity. In this study, we confirm low genetic diversity in the innate immune region of African penguins similar to that
observed in New Zealand robin that has undergone several severe population bottlenecks.
Single nucleotide polymorphism (SNP) diversity across TLRs varied between ex situ and in
situ penguins with the number of non-synonymous alterations in ex situ populations (n =
14) being reduced in comparison to in situ populations (n = 16). Maintaining adaptive diversity is of vital importance in the assurance populations as these animals may potentially be
used in the future for re-introductions. Therefore, this study provides essential data on
immune gene diversity in penguins and will assist in providing an additional monitoring tool
for African penguin in the wild, as well as to monitor diversity in ex situ populations and
to ensure that diversity found in the in situ populations are captured in the assurance
populations.