The mixed-mating model is a
mathematical model
A mathematical model is an abstract and concrete, abstract description of a concrete system using mathematics, mathematical concepts and language of mathematics, language. The process of developing a mathematical model is termed ''mathematical m ...
that describes the
mating system
A mating system is a way in which a group is structured in relation to sexual behaviour. The precise meaning depends upon the context. With respect to animals, the term describes which males and females mating, mate under which circumstances. Reco ...
of a plant population in terms of degree of
self-fertilisation
Autogamy or self-fertilization refers to the fusion of two gametes that come from one individual. Autogamy is predominantly observed in the form of self-pollination, a reproductive mechanism employed by many flowering plants. However, species of ...
. It is a fairly simplistic model, employing several simplifying assumptions, most notably the assumption that every fertilisation event may be classed as either self-fertilisation, or
outcrossing
Out-crossing or out-breeding is the technique of crossing between different breeds. This is the practice of introducing distantly related genetic material into a breeding line, thereby increasing genetic diversity.
Outcrossing in animals
Out ...
with a completely
random
In common usage, randomness is the apparent or actual lack of definite pattern or predictability in information. A random sequence of events, symbols or steps often has no order and does not follow an intelligible pattern or combination. ...
mate. Thus the only model
parameter
A parameter (), generally, is any characteristic that can help in defining or classifying a particular system (meaning an event, project, object, situation, etc.). That is, a parameter is an element of a system that is useful, or critical, when ...
to be
estimated
Estimation (or estimating) is the process of finding an estimate or approximation, which is a value that is usable for some purpose even if input data may be incomplete, uncertain, or unstable. The value is nonetheless usable because it is de ...
is the probability of self-fertilisation.
The mixed mating model originated in the 1910s, with
plant breeders
Plant breeding is the science of changing the traits of plants in order to produce desired characteristics. It is used to improve the quality of plant products for use by humans and animals. The goals of plant breeding are to produce crop varie ...
who were seeking evidence of
outcrossing
Out-crossing or out-breeding is the technique of crossing between different breeds. This is the practice of introducing distantly related genetic material into a breeding line, thereby increasing genetic diversity.
Outcrossing in animals
Out ...
contamination of self-pollinating crops, but a formal description of the model and its parameter estimation was not published until 1951. The model is still in common use today, though a number of more complex models are also now in use. For example, a weakness of the model lies in its assumption that
inbreeding
Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely genetic distance, related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genet ...
occurs only as a result of self-fertilisation; in reality, inbreeding may also occur through outcrossing between closely related individuals. The
effective selfing model relaxes this assumption by seeking also to estimate the degree of shared ancestry of outcrossing mates.
References
Plant sexuality
Mating systems
Mathematical modeling
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