Sex, Death and Secret Identities
Roles for genetics in conservation
Alyssa Mitchell
What is Conservation Genetics?
• Integrative• Variation• Intra & inter population
Effective Population Size• Adaptability is related to variability• Hunted to near extinction• 20-30 left• 175 000 now• Ne = 60• What does
this mean for them?
Breeding
• Inbreeding• Mating vs breeding• Blanding’s Turtles are promiscuous, but
only about 5% of males are producing offspring!
Hybrids• Increase in variation• Dilute deleterious alleles• Florida panthers got a little help from
Texas cougars
Cryptic Species
• How do we know??• In this case, all it takes is a
karyotype!
Population Distinction• Who meets?• Who mates?• And who cares???
Microsatellites
• Simple-sequence tandem repeats• Highly variable & mutable• Locus-specific• Highly heterozygous• Biparental nuclear variation• CACACACACACACACACACACACACA…
Mitochondrial DNA
• Many genes are highly conserved• (Usually) Uniparental & matrilineal
variation• Species ID & phylogeny• Operation Shrew Poo!
Nova Scotian Shrews
• Nova Scotia is home to seven species of shrews, most of which are sympatric.
• Sorex cinereus is the common shrew, found in most of the province, including some islands.
• Sorex fumeus is knownas the smokey shrew,and smells worse thanany other!
Nova Scotian Shrews
• Sorex dispar is a talis slope specialist• Sorex hoyi is the American pygmy
shrew & among the smallest land mammals in the world
• Blarina brevicauda is a short-tailed shrew with a venomous saliva that seems to have anti-cancer properties.
Sorex Palustrius
• American water shrew• One of the
only species todive & foragein water.
• Not endangeredoverall
Sorex maritimensis
• Maritime shrew• Endemic• Likely endangered• Recently elevated to species status
The Goal
• To determine the distribution of these two species of shrews in Nova Scotia
• Data points few & far between
General Characteristics of Shrews
• Very low body weight for land mammals
• High metabolism• Easily stressed• Can be scared to death• Most active at night
Obstacles to Research
• Trapping• Identifying• Holding in
captivity
Dr. Churchfield to the Rescue
• Dr. J Sara Churchfield’s Water Shrew Survey
• UK Mammal Society• Amassed volunteers & collected
scats• Used scat morphology• Volunteers submitted
reports
Fecal DNA & Molecular Markers
• Two students developed some species-specific primers & an RFLP-based protocol
• Mitochondrial DNA : more copies, well-known cytochrome b gene
Fecal DNA & Molecular Markers
• What happened??• DNA quality• New protocol!
BamHI cuts Sorex palustris only
XbaI cuts Sorex maritimensis only
Much easier to amplify
100 & 200 bp fragments indicate that a cut site has been recognized
Forensics
• What is it, and where did it come from?
• CSI: Whale
Captive Breeding
• Avoid inbreeding• Encourage specific alleles
Success!
• Out of danger• ID a threat• Increase genetic variation
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