Aquaculture and Fisheries Management
- Stock / Strain Identification
- Hybrid Differentiation
- Estimation of Genetic Variation
- Screening for Markers for Production Traits or Genetic
- Individual Identification
The DNA testing services offered by Therion International have dramatically enhanced
the ability to answer questions of identity in aquatic animals. DNA-based tests are more
powerful than conventional blood protein and isoenzyme analysis because they detect highly
variable DNA sequence information. Aquaculturists and fisheries scientists can further
refine their production and management efforts through the acquisition of data concerning
genetic identity/variation at the individual, stock or species level.
Depicted below are examples of results produced from
several studies concerned with the genetics of aquatic animals.
|The DNA profiles of four individuals from each of
three populations of coho salmon (figure to the left) were compared to see if the
populations could be distinguished from one another genetically. DNA was isolated from the
blood of each individual and cleaved with the restriction enzyme Hinf I. These fragments
were then separated on a 1% agarose gel and transferred to a nylon membrane. The membrane
was hybridized with Therion's proprietary DNA probe, OPT-06, washed and exposed to
x-ray film. The lanes labelled MWSS contain molecular weight sizing standards. Three
genetic markers (yellow bands) were observed in 50-75% of "C" individuals
tested, but were not observed in any "BQ" or "F" salmon. One genetic
marker (green bands) was found to occur in all "BQ" coho but not in any of the
other coho populations. In addition, 75% of "F" coho salmon exhibited a specific
genetic marker (blue bands) which did not appear in any individuals from the "C"
or "BQ" population. In conclusion, Therion's DNA testing services make it
possible to readily differentiate among these stock populations.
|A study was conducted to identify genetic markers
that could differentiate among individuals representing two populations of striped bass.
The figure to the left shows the DNA profiles of 11 striped bass generated with
probe/enzyme combination OPT-05/Hae III. All individuals from Population 1 display
bands in the region above 6.6 kb. None of the individuals from Population 2 have bands in
this area, thus the two populations can be genetically distinguished by the presence or
absence of bands in the region above 6.6 kb.
|A client was concerned about the potential loss of genetic
variation within a captive strain of Penaeus stylirostris. The figure to the right
compares the DNA profiles of six shrimp from a captive population to six shrimp from a
wild population. These profiles were generated with the probe/enzyme combination
OPT-05/BstN I. Within the captive strain, genetic variation is less than 15%; note
that each genetic marker is shared by nearly all individuals. The wild strain shows
significantly more genetic variation than the captive population. Therion was able to
estimate the level of genetic variation using its proprietary computer softwares which
analyze and quantify DNA profile banding patterns. From these data, genetic parameters
such as indices of bandsharing, heterozygosity and genetic distance can be derived to
estimate genetic variation and relatedness.
|Whole Blood containing:
||1 - 2 ml
purple top Vacutainer
overnight on ice packs
Frozen - overnight on dry ice
(suggest fin clips)
||1 - 2
tube/vial with 70% ethanol
or second day
||Call for instructions