The inheritance of acquired characteristics was dismissed upon the discovery of genetic inheritance, but it is now evident that the environment, experience and even behaviour of parents can influence the characteristics of their offspring – a phenomenon known as “nongenetic inheritance”. I am interested in how these nongenetic
sources of variation influence both male and female reproductive investment and mating strategies.
Until recently, sperm were essentially thought of as a vehicle – delivery of the male DNA to eggs being their only job. It was assumed that sperm quality influences fertilization success, but that only a male’s genes could influence his offspring. My research has challenged this assumption, using sea-squirts to empirically demonstrate that a male’s environment influences the quality of his sperm, and that sperm quality influences the development and viability of offspring.
Sperm are delivered in seminal fluid, which contains a cocktail of proteins, sugars, enzymes and hormones. These seminal compounds can alter female physiology and behaviour, and influence offspring development. As semen is not tied to fertilization, males may influence the development of offspring via this cocktail of seminal components… even if their sperm does not fertilize the egg. My research has demonstrated that offspring size in neriid flies can be influenced by a previous mating partner (i.e. a male who is not the genetic sire) of their mother, reinvigorating the theory of telegony.