Biology Reference
In-Depth Information
effects seen in those analyses translate to parallel population genetic effects
observable when loci with fewer alleles of higher frequencies are used.
Dioecious value = “true”
The above statement designates that the species under study is dioecious
(each individual is either one sex or the other). If true, selfi ng is automatically
prohibited. When the statement value is set to “false”, all individuals
are bisexual, and rate of selfi ng is determined by a statement described
below.
If the population is designated as being dioecious, each founder can
be assigned a permanent male or female role later in the statements where
the spatial location of each founder individual is given (initial population
statements described below). If dioecious is designated as false, the male
or female assignment made when the spatial location of each founder is
given is neglected, with each founder then being capable of acting as both
male and female. Whether the dioecious value is set to true or false, all
newly generated offspring are randomly designated as being either male
or female in a 1:1 ratio. Those designations are stored, but do not apply,
when the dioecious value is set to false.
Dioecy: Some Theoretical Considerations
In many organisms, it is clear whether the species is monecious or dioecious.
NEWGARDEN is not yet designed to accommodate more complex
situations (e.g., andro- or gynodioecy). Users may have prior information
that, for a particular dioecious species or situation, founding sex ratios
are skewed. The initial population input statements allow one to adjust
the frequencies of micro- versus megagamete contributors to match wild
populations, or to study the effects of variation in sex ratios on conservation
genetics under differing population development conditions (e.g., in
annuals versus perennials). If the founders of a population are dioecious
with a skewed sex ratio, since females produce a ratio of males to females
in a 1:1 proportion, later generations will usually approach a 1:1 ratio
rapidly (in one generation for annuals), unless there is an extreme excess
of male founders in perennial populations, and/or there is low production
of offspring relative to the founders.
Reproduction Rate
The rate of production of single offspring (e.g., the production of a single seed
before establishment) is controlled by the Reproduction_Rate statements
in the data input fi le. For seed plants, this would refer to reproduction via
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