9314

• UCREFRP Catalog Number: 9314
• Author: Wick, E. J. and J. A. Hawkins.
• Title: Colorado Squawfish Winter Habitat Study.
• USFW Year: 1989.
• USFW - Doc Type: Fort Collins.
• Copyright Material: NO

EXPLANATION OF FIGURE 2
The 5 X 5 Di-Allele Breeding Matrix
Over generations, genetic diversity can decline in captive populations
from the original founders through uncontrolled matings. Controlled
breeding using marked broodstock, paired matings, equal sex ratios, and
equal numbers from pedigreed family lots can help to reduce any nega-
tive effects to the original genetic diversity.
1. Ten unrelated parents, five males (columns) and five females
(rows) are bred using a 5 X 5 matrix - the "di-allele" cross
(Kapuscinski et al. 1993).
2. Effective population size is 10.
3. The figure illustrates a single locus. multi-allelic (10 unique
allele) system. Each unique allele is represented in the figure
with a different color.
4. Each parent in this illustration is limited to two alleles that
are homozygous.
5. 25 heterozygous F lots or genotypes are produced by the matings,
resulting in all possible genotypes.
6. The breeding matrix produces half-sib maternal (within rows) and
half-sib paternal (within columns) F family lots.
7. Breeding within family lots (brother/sister or full-sib matings
(i.e., mating an Al male with an Al female) results in inbreed-
ing in the F generation. See lower left illustration in Fig. 3.
Inbreeding results in an increased frequency of homozygous
genotypes and a decreased frequency of heterozygous genotypes.
This results in an increased frequency of familial alleles and
a loss of population alleles, with a loss of fitness in offspring
because of increasing deleterious recessive alleles.
8. If another population is founded from a limited gene pool, the
new population (i.e., broodstock) would suffer the effects of a
"founder event".
9. Breeding within a row or column produces half-sib matings (i.e.,
mating an Al male with an A2 female). that also results in
inbreeding, but not to the extent of brother/sister matings.
Homozygosity increases at a reduced rate when compared to
full-sib matings. See lower center illustration of Figure 3.
10. Mating progeny from outside columns and rows prevents inbreeding.
All F family lots are heterozygous and genetic diversity is
maintained. See lower right illustration in Figure 3.
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