genetics

History of deer colonization - Response of vegetation to deer - Response of animals to deer and squirrel - Deer biology

Menu: Home; Haida Gwaii; Introduced Species; RGIS; What did we learn?; Research; Publications; RGIS symposium; School curriculum; Contacts
English
Français

Deer density and movement - Deer genetic and morphometric variations

Deer genetic and morphometric variations

Aim & scope - Where & when - How - Main results - Conclusion - Scientific Publications

Aim and scope

Deer culls on Reef and SGang Gwayy were an opportunity to collect morphometric data and biological samples in order to provide basic biological knowledge about deer population on Haida Gwaii.

These data could provide information on deer colonization rates, health and inbreeding level.

return to top of page

Where and when

Morphometric data and biological samples were systematically taken on animals killed during hunts on Reef Island (1997, 1998, 1999, 2006, and 2007) and SGang Gwayy Island (1998, 1999).

Tissue samples for genetic analysis were obtained from 150 deer. 60 of them were from Reef Island, 38 of them were from SGang Gwayy, which represented the majority of the deer population of each island. In addition, 33 deer were sampled on Louise Island, the most probable source population for migration of deer to Reef Island, and 19 deer were sampled on the South end of Moresby Island, the most probable source of animals colonizing SGang Gwayy.

return to top of page

How

The following data were recorded on killed individuals:

General information (sex, age)
Morphological data (skull measurements, body weight, body length, shoulder height, tail, hind leg and ear lengths, front body circumference)
Biological data (body, udder and uterus conditions, presence of external parasites, signs of disease and deformities)

In addition, were collected:

udder, uterus/ovaries, kidney fat, kidney and liver
rumen and mouth contents
fecal, blood, skin and tooth samples
muscle, liver or hide sample for DNA analysis

return to top of page

Main Results

Killed sex ratios
Reef: 1.05 males / females; SGang Gwayy: 0.375 males/ females

Balanced sex ratio on Reef, but highly skewed on SGang Gwayy.

Pregnancy rates
Reef: 36%; SGang Gwayy: 28%

Very low rates compared to other populations.

Parasites, diseases, deformities

Exceptionally low incidence of disease / parasites and very limited evidence of inbreeding deformities.

Body condition

Weight, length and body condition showed signs of nutritional stress.

Other morphometric data have not been analysed yet.

Deer dispersal

10 microsatellite DNA markers were analyzed in tissue samples from deer coming from Reef Island, Louise Island, SGang Gwayy and the south end of Moresby Island.

Microsatellite DNA is often used as a marker in genetic analysis, because each locus can display many different alleles.

By comparing allelic diversity for these 10 microsatellite DNA markers between the main “source” islands (South Moresby and Louise) and the offshore islands (SGang Gwayy and Reef), we can infer the frequency of population exchanges between them.

The alleles carried by an individual are identified through the electrophoresis of the DNA extract.

Elecrophoresis consists in making a DNA extract migrate in a gel.
As different alleles do not have the same size, they migrate at different speeds; consequently, the smaller alleles migrate further than the larger.

A reduced allelic diversity on the offshore islands compared to the source populations would mean a low rate of colonization from the main islands. On the contrary, a similar allelic diversity would mean a high rate of colonization.

Very similar allelic diversity and allele frequencies were found between SGang Gwayy and Moresby Island, Reef and Louise islands, and SGang Gwayy and Reef Island.

The number of migrants per generation suggested by these results was 2.23 between Moresby Island and SGang Gwayy, and 3.22 between Louise Island and Reef Island.

As a generation of deer is 2 or 3 years, the migration rates must be approximately one individual per year.

return to top of page

Conclusion

Health condition

signs of nutritionnal stress on Reef and SGang Gwayy populations
but relatively low parasite loads and little disease.

Inbreeding evidences

Morphometric data have not been analyzed yet.

Colonization rate

about 1 immigration event per year on Reef and SGang Gwayy, a dispersal rate that will reduce the efficiency of deer removal programs.

return to top of page

Scientific Publications

See symposium proceedings - PDF

return to top of page