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