Genetic Diversity – Further Reading

The Cleveland Bay is among the horse breeds classified as Critically Endangered

General Information Sites

The Livestock Conservancy
This organization offers a wealth of educational resources

European Farm Animal Biodiversity Information System (EFABIS)
This site has extensive census information on various breeds of livestock, including horses

The Canine Diversity Project
Extensive listing of articles on the subject of genetic diversity as it relates to the breeding of purebred dogs. Most are written for laymen, particularly those breeding dogs.


Pedigree Dogs Exposed
Few things have generated as much attention for issues of genetic diversity as this BBC documentary. Public reaction in the United Kingdom led to a number of studies and, most recently, very controversial changes to show ring procedures. Warning: Contains scenes that some may find upsetting. A follow-up was made in 2011, and can be purchased here.

Morphological Changes
This video shows the morphing of a gray wolf skull into that of a French Bulldog.

General Interest Articles
(not peer-reviewed)

The Poodle and the Chocolate Cake
This article is a short, very readable overview of why genetic diversity is an issue in purebred animals, using Standard Poodles as an example.

Significant Relationships
This is probably one of the best “plain English” explanations of inbreeding coefficients and what they really mean in terms how two animals are related. (Opens as a .pdf file)

Eliminating Mutation – The Impossible Dream
Like the above two articles by the same author, this one is very straight-forward and covers a broad range of topics relevant to genetic diversity, including the founder effect, genetic drift and inbreeding depression.

Purebred Dogs into the Twenty-First Century
This article ties together issues surrounding genetic diversity and the current culture of purebred dog breeding, and offers potential solutions. Be sure to follow the links at the end, since it is long four-part article.

Breed-Specific Sites and Articles
(not peer-reviewed)

Genetic diversity of the Irish Draught Horse population and preservation of pedigree lines
This report prepared for the Irish Draught Horse Society contains interesting information on the breed’s relationship to other Celtic breeds, including ponies, as well as a handful of Spanish breeds. (Opens as a .pdf file)

Is subfertility or infertility relatived to chromosome abnormalities in the Sorraia Horse? (Opens as a .pdf file)

Bygone Bulldogs
This is a South African site devoted to exploring the changes in the English Bulldog. The extensive collection of skeletal comparisons are of particular interest. (It should be noted that structural extremes are a separate, but interrelated issue when it comes to producing healthy animals.)

Genetic diversity in the Przewalski’s Horse

Inbreeding coefficients for ROM Shetland Sheepdogs

Old-Time Farm Shepherd
This website holds the archives for the Farm Collie Movement, which began online in the mid-1990s with sites like the Once and Future Collie, Friends of the Old Farm Collie and the Classic Victorian Collie Club.

Outcross and Backcross Experiments

The Dalmatian Backcross Project
This project was started in 1973 to reintroduce the gene for normal uric acid (LUA) in Dalmations using a cross to a single purebred Pointer.

The Bobtail Boxer Project
This series of articles details attempts to introduce the bobtail gene in Boxers using Corgis. The images are of particular interest, since they show how quickly the Boxers returned to type despite such an extreme outcross. (The bobtail mutation was later shown to be a homozygous lethal, as detailed in this peer-reviewed paper.)

The Basenji African Stock Project
This project was initiated to expand the very limited founder animals (7 males, 5 females – not all of which bred forward, some probably already related) in the Basenji breed.

Society for the Perpetuation of Desert Bred Salukis
This group promotes the use of Salukis imported from the Middle East in Western breeding programs. Further information on history of the Desert Bred Saluki Critique Program and its relationship with the Saluki Club of American can be found here.

Peer-Reviewed Papers
Most of these links take you to articles of a more technical nature, though the introduction and conclusions often contain information that laymen can find helpful. Most open as .pdf files.

Whole mitochondrial genome sequencing of domestic horses reveals incorporation of extensive wild horse diversity during domestication (2011)
This study suggested that an unusually high number of wild founder mares – at least 46 – contributed to the modern domestic horse.

Conservation genetics of endangered horse breeds (2005)
Published by the European Association for Animal Production, this is a collection of papers on genetic diversity and some of the endangered horse breeds. Along with general topics, there are papers on the Kladruber, Lipizzan, Connemara, Akhal-Teke, Italian Heavy Draft, as well as Norse and British native breeds.

European domestic horses originated in two Holocene refugia (2011)
This study examined the genetic diversity in 24 different European breeds, and identified two potential hot spots that contributed to the development of modern horses. A news article on the findings can be found here.

History of Lipizzan horse maternal lines as revealed by mtDNA analysis (2002)
This study looked at dam lines in the Lipizzan, which has a pretty broad genetic base with 56 maternal lines representing 37 different haplotypes. The study also identified likely pedigree errors which suggested that lost female lines might still exist in the modern breed.

Genetic diversity of a large set of horse breeds raised in France assessed by microsatellite polymorphism (2009)
This study looked at 34 different French breeds from four different groups (warmblood, draft, Nordic and pony) to assess conservation priorities.

Genetic diversity and bottleneck studies in the Marwari horse breed
Marwaris show a high level of diversity, which suggests the breed has not undergone recent population bottlenecks.

Inbreeding and genetic structure in the endangered Sorraia Horse breed: implications for its conservation and management

Genetic Disease in Horses
Please be aware that some of these links may contain disturbing images

Hairless Foal Syndrome (Akhal-Tekes) 
Junctional Epidermolysis Bullosa (JEB) (Belgians and other draft breeds)
Junctional Epidermolysis Bullosa (JEB2) (Saddlebreds)
Wobbler Syndrome (Akhal-Tekes)
Hyperkalemic Periodic Paralysis (HYPP) (descendants of Impressive AQHA)
Cerebellar Abiotrophy (CA) (Arabians)
Polysaccharide Storage Myopathy (PSSM) (American stock horse breeds)
Hereditary Equine Regional Dermal Asthenia (HERDA) (descendants of Poco Bueno AQHA)
Glycogen Branching Enzyme Deficiency (GBED) (descendants of Zantanon AQHA)
Myotonia (New Forest Ponies)
Severe Combined Immunodeficiency Disease (SCID) (Arabians)
Foal Immunodeficiency Syndrome (FIS) (Fell and Dales Ponies)
Dwarfism (Friesians)

Color-Related Disorders
Lavender Foal Syndrome (LFS) (Arabians, primarily Egyptian lines)
Lethal White Overo Syndrome (LWOS) (homozygous frame overos)
Congenital Stationary Night Blindness (homozygous appaloosas)
Equine Recurrent Uveitis, or “Moon Blindness” (appaloosas in higher numbers)
Multiple Congenital Ocular Anomalies (MCOA, formerly ACD) (silver dilutes)