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