Born to Gait

23/10/2023

10/10/2023

REGIONAL NEWS

Born to Gait Magazine (Fall 2023 Issue)

This section is yours and it's free! Send one or two high-resolution photos to [email protected] with a short paragraph. Please, PPR Paso Fino horses living in the continental United States and Canada only.

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The Pure Puerto Rican Paso Fino is an endangered breed of horse recognized by The Livestock Conservancy and Equus Survival Trust.

is a free digital publication dedicated to promoting the Pure Puerto Rican Paso Fino Horse Breed in the United States.

Read the Versatility Issue at https://issuu.com/borntogait/docs/fall_2023

Subscribe at https://mailchi.mp/801e14b3d828/borntogait-subscribe

09/10/2023

VERSATILITY AND DIVERSITY: RATIONALE FOR BREED PRESERVATION

Xiomara R. Arias | Born to Gait Magazine (Fall 2023 Issue)

Versatility – what comes to mind when you think of this word? If you like movies, perhaps a Transformer comes to mind, transforming from car to robot! Perhaps you are on the more practical end of things, and a Swiss Army Knife comes to mind, knife, toothpick, file, screwdriver, and all. Maybe your mind (much like mine) never deviates from thinking about horses and you immediately think of 3-day events – dressage, cross-country, and show jumping. Despite the word “versatile” applying to a plethora of concepts, its meaning is never diminished. Versatility is the ability to adapt to new events and be flexible in skills. This definition applies well to the Puerto Rican Paso Fino. Versatility is greatly prized among horse breeders and associations. Versatile horses must demonstrate the ability to be flexible in mind and body. The best versatile horses, to modify an old quote, are jacks of all trades and masters of some! The Puerto Rican Paso Fino is my favorite horse to ride, whether I am competing at a gallop, playing around at a canter, or reflecting at a calming 4-beat gait. Perhaps one of the only events they cannot do is race —but I’m happy to leave that to the Thoroughbreds! Let’s take a look at some examples of demonstrated versatility in our breed.

Mr. Clifford Fischer has trained Puerto Rican Paso Finos to be police horses. Their size may be an impediment to field work (most police horses have draft blood), but the Puerto Rican Paso Finos can be trained to pass the police horse test. One of Mr. Fischer’s horses even broke a state record in completion time for the obstacle test. I have heard repeated time and again that not every horse can be trained to be a police horse. Despite the size limitations, it is important to note that the Puerto Rican Paso Fino has the ability and intelligence to be trained as a police horse. Mr. Clifford has also shown Puerto Rican Paso Finos to be well-adapted to endurance races. I am thankful that Mr. Fischer has taken the time to train his horses well and demonstrate their versatility.

The versatility of the Puerto Rican Paso Fino is being demonstrated in Puerto Rico by Nicole Aviles, her students, and Nora Marrero. These women are pioneering the way for Puerto Rican Paso Finos in competitions such as dressage, jumping, and barrel racing. The elegant, precise, and fluid gait of the Paso Fino is perfect for such events.

Puerto Rican Paso Finos have also been trained to compete in rodeo events. Randee Randall in Oregon has trained her Puerto Rican Paso Fino to barrel race, pole bend, run keyhole, and cut cattle. Randee has used the same rodeo horses with search and rescue operations. Being able to show up and run a rodeo event and then be a calm and level-headed search and rescue companion demonstrates an amazing amount of versatility for a single horse.

Would you believe that Puerto Rican Paso Finos are often naturally cowy? I have heard on two different occasions of completely different Paso Fino bloodlines that Quarter Horse trainers were impressed by a specific Paso Fino’s “cowiness”. Randee proudly shows her horse’s aptitude for working with cattle on Facebook. Paso Finos were developed as family AND work horses, with cattle handling being an important part to the work aspect.

Let’s talk about one of my favorite pastimes. Many trail riders self-deprecate by indicating that they “just” trail ride, and their horses are “just” trail horses. In reality, most trail horses are extremely well trained. Many hours go into training a horse to focus on the rider and be desensitized to stimuli. Some aspects of a trail horse are by blood, such as good-footedness and a predisposition to endurance – both of which Puerto Rican Paso Finos naturally have! Other aspects are purely developed by training, and require a moldable mind. The Puerto Rican Paso Fino is an excellent choice for a smooth, intelligent trail partner. Just sit back and enjoy the scenery!

Humans often mistake intelligence for willingness to obey our will. I would argue the exact opposite. Intelligence in animals is the ability to demonstrate thinking for themselves. Truly intelligent animals are the most rewarding for which to develop a relationship. You know that they are not blindly following commands, but have thought and decided that they will put their trust in their rider. I’ve heard some ascribe pig-headedness to the Puerto Rican Paso Fino, not willing to ride a breed that is naturally intelligent and deserves more than being forced to complete tasks mechanically. You are more than welcome to ride an animal that has given up their will, but I would rather have a discussion with my horse and be companions. The Puerto Rican Paso Fino is an intelligent partner.

I apologize, but I can’t get through an article without talking about my partner in crime, Omega! Omega is by no means the perfect horse (though he is in my heart!) but I believe he is still a good example of versatility. I can throw him into any class and know he will work his heart out for me. At the Celebration Show in South Carolina, he has won Horse of the Show for two years, and won the 2022 Horse of the Show at the local Pioneer Saddle Club show. Being eligible to win these awards demonstrates that he can compete in a wide range of events. During the Celebration Show Omega went from winning Bellas Formas to winning the Panty Race (my personal favorite class), to competing in Excellence of Gait, to winning Egg and Spoon, and to the Gelding’s Pleasure Championship. Conformation and ground manners, gait ability, speed, and smoothness of gait are tested in these classes, and Omega did not disappoint! Upon returning home, he nobly allowed my young nieces to ride him. He goes from champion to child’s horse! I know there are plenty of Pasos that can demonstrate the same ability, if not better. Come beat Omega for Horse of the Show! Let’s show off the Paso Fino’s versatility and make each other better with friendly competition.

Within the Puerto Rican Paso Fino there is a wide range of diversity. I believe it would be rather monotonous to have a completely homogeneous breed. The diversity within our breed is complex, interesting, and worth conserving. The variations in phenotype make it possible for breeders to develop their ideal horse. I feel fortunate to live in an age where genotype can inform decisions made for a specific phenotype, though just the topsoil of horse genetics has been uncovered. Within our breed we have variations in size, temperament, conformation, gait, and color. The differences between the three main Puerto Rican Paso Fino populations (Eastern mainland U.S., Western mainland U.S., and Puerto Rico) allows breeders to maintain old bloodlines and refresh linebreeding with new blood. While variations exist, the Puerto Rican Paso Fino breed has it fixed within their blood to be intelligent, adaptable, and beautiful (though I may be biased on the last characterization). You, the owner, can mold the horse to your ambitions. We won’t know the extent of the breed’s versatility without trying new events and pushing the limits of what is deemed possible for the Paso Fino.

Now, if you are reading this you may already fully understand the magnificent versatility of the Puerto Rican Paso Fino. However, there are those who have not discovered our fascinating breed. In my opinion, it is unfortunate that not everyone has had the opportunity to explore the Puerto Rican Paso Fino. As owners, it is our job to display the breed and help others gain awareness of the Paso Fino’s unique qualities. How can we do this? Breed promotion is a crucial part to conservation. In the mainland United States, owners can show their horses in parades during events such as Christmas and 4th of July celebrations. In Puerto Rico, cabalgatas (horse parades) can be held to show camaraderie among Paso Fino owners. The main idea is to promote the breed by using your horses in the public eye – the horse's versatility will speak for itself.

The origin of the Paso Fino and its development as a breed is attached directly to the 4-beat lateral gait. This gait adds an extra level to the breed’s versatility. The Paso Fino can be an excellent trail horse, surefooted and brave. They can show, jump, run speed events, and even be police horses. But, the most special part is that they can do all these tasks with comfort for the rider. The Puerto Rican Paso Fino was bred to be a versatile family horse. When I ride my horse, work in the barn with my dad, or go to shows, I am filled with proud fervor towards this breed of horse. It is my responsibility to preserve my culture and heritage, and for me that starts with the Puerto Rican Paso Fino. The versatility of the Puerto Rican Paso Fino knows no bounds, provided you have a conversation and teach them how to execute their job. Join the Puerto Rican Paso Fino family and let your Paso take you to new horizons!

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The Pure Puerto Rican Paso Fino is an endangered breed of horse as recognized by The Livestock Conservancy and Equus Survival Trust.

is a free digital publication dedicated to promoting the Pure Puerto Rican Paso Fino Horse Breed in the United States.

Read the Versatility Issue at https://issuu.com/borntogait/docs/fall_2023

Subscribe at https://mailchi.mp/801e14b3d828/borntogait-subscribe

08/10/2023

THE GENETICS OF THE COLOR SPECTRUM IN OUR PUERTO RICAN PASO FINOS

Paola Matos Ruiz & Xiomara R. Arias | Born to Gait Magazine (Fall 2023 Issue)

The genetics article in the previous magazine issue focused on the genetics of tiger eyes, which is a unique trait of the Pure Puerto Rican Paso Finos. In this article, we plan to continue promoting the genetic diversity of the Pure Puerto Rican Paso Fino breed by exploring the genetics of coat colors and blue eyes. We also plan to illustrate the genetics of coat and eye color through a case-based learning series using a Pure Puerto Rican Paso Fino cremello horse as an example.

Mutations. We hear this word and may have vastly different impressions of what it means. Do you think of ugly mutants, abominable creatures that come from the depth of toxic waste? When we are children, this is what may have come first to our minds. Despite being perceived as atrocious by some, mutations allow the world to be filled with diverse beauty and benefits for species’ survival. Divergent biological aspects create a planet with many new and appealing sights. Our world would not be nearly as beautiful or diverse without the possibility of mutations. Due to mutations, we have the diversity of coats and eye colors we appreciate nowadays in horses.

Red and black are the primary pigments in horses’ base coat colors. The interaction of the genes Melanocortin Receptor 1 (MC1R, abbreviated as E) and Agouti-signaling protein (abbreviated as A) determines the base coat color in horses.1-2 How these genes are co-inherited dictates the final base coat color product.

The MC1R gene plays a role in determining the black and red pigments and is known as “extension” or the red factor locus. Three alleles are known for the base coat color dictated by the MC1R gene: E, e, and ea. Two copies of the recessive alleles (e/e, e/ea or ea /ea ) alleles would produce only horses with a red base coat color (e.g, chestnuts, palominos, red duns) because this genotype masks the expression of other genotypes that could be co-inherited through a genetic mechanism known as epistasis. The Agouti gene determines the distribution of black pigmentation in horses and acts as a modifier to determine bay versus black. From the absence of the Agouti dominant copy (A/a or A/A) and recessive red factor alleles (e/e, e/ea or ea /ea ), we can get black horses if the horse genotype at the MC1R gene is E/E or E/e. In the presence of one or two copies of Agouti (A/a or A/A) and one or two for the MC1R gene (E/e or E/E), the horse may have a bay color phenotype with black pigmentation restricted to the mane, tail, lower legs and ear rims. These areas of black pigmentation are referred to as “points”. In other words, Agouti modifies the black pigmentation on the horse's body, except for the points mentioned above.

While black and red (also known as eumelanin and pheomelanin, respectively) are the only pigment types present in horses, mutations can cause a different distribution of pigments, resulting in our diverse color wheel of horse hair. For example, the cremello, smoky black, smoky cream, and perlino colors are the results of a mutation, primarily affecting the Cream locus9-10.

The Cream (C) locus located in chromosome 21 is where the Cr and N alleles are found.9-10 Cr refers to an allele with a variant in the MATP gene that produces color dilution, whereas N refers to an allele without the variant.9-10 Since horses are diploid, they will inherit an allele from each of their parents. The Cream locus can present a different phenotype for homozygotes (e.g., Cr/Cr) and heterozygotes (Cr/N). For example, if a horse is homozygous for the Cream allele (e.g., Cr/Cr), it means it has two copies of the Cream dilution variant. Depending on the base coat color (e.g., chestnut, bay, or black) the homozygous (Cr/Cr) horse would be expected to be cremello (chestnut base), perlino (bay base), or smoky cream (black base). If the horse is heterozygous, Cr/N, it has one copy of the Cream dilution allele, it would be expected to be either palomino (chestnut base), buckskin (bay base), or smoky black (black base). If the horse is recessive for the absence of the variant at the Cream dilution locus, N/N, its phenotype should show its base coat color.

The presence of two copies of the Cream dilution allele at the C gene locus does not render a horse an albino. Albinism refers to the inability to produce pigment and, therefore, a complete lack of color, which presents itself as white. The presence of Cream does not result in the absence of color; rather, it changes the distribution of pigment. Albinism is currently not a phenomenon that has been described for horses. Although from manifestations in other species, albinism often causes reddish/pink eyes.11 Cremello and perlino horses have blue eyes, therefore demonstrating that they are not albinos.

Pintos, similarly, are a result of a variety of genetic mutations. The patterns of pintos that have been observed in the Puerto Rican Paso Finos are: Tobiano pintos (TO), Sabino pintos (SB1) and Dominant White 20 (DW20). Tobiano pintos are a result of a chromosomal inversion in chromosome #3.8 The specific genetic mutation observed in our breed’s Sabino pintos has not been identified, but it might involve the KIT gene. The Sabino mutations tend to vary among horse breeds; the specific mutation for the Pure Puerto Rican Paso Finos has not been identified scientifically, but we predict it might involve the KIT gene.4 The DW20 results from a point mutation at the KIT gene (c.2045G>A) and results in prominent white markings in the leg and face, more in its homozygous form than its heterozygous form.3 From talking to breeders in Puerto Rico who own offspring of the Grand Sire of the Breed, Linaje D’ La Excelencia, the DW20 mutation has been confirmed genetically through genetics panels ordered by the breeders themselves. Based on pedigree analysis, most likely, Linaje is a carrier of this mutation because of his paternal grandmother, Jackeline.

So far, research has not found evidence about the Tobiano, Sabino, and DW20 mutations resulting in adverse health effects. In contrast, gray horses, which have also been observed in our breed, do experience adverse effects by being at a higher risk of developing melanomas in their lifetime due to depigmentation of their skin. Gray horses are a result of a mutation (i.e. duplication of intron 6) in the gene syntaxin 17 (STX17) that results in progressive depigmentation of the skin by inhibiting the production of melanocytes.5-6 They are born gray and progressively their hair color transforms to white. The pattern of inheritance is autosomal dominant, which implies you only need one copy of the mutated allele of gene STX17 to develop this pattern. In other words, they lose their hair pigmentation which serves as an armor to protect their bodies against the dangerous sun UV light and are prone to develop skin cancer. According to most recent research, 70-80% of gray horses will develop melanoma (skin cancer) by the time they are 15 years old.5-6 It is important to clarify that some of the skin tumors gray horses develop are benign; about 66% become malignant.7

To current knowledge, there are only two Pure Puerto Rican Paso Fino double cream diluted stallions worldwide. They are both cremellos, with Sueño de Paz residing in Puerto Rico and Rayito de Oro residing in the mainland United States. Sueño de Paz sire is the palomino stallion Ensueño Dorado and palomino dam Platanera Dorada. Rayito de Oro is the son of the palomino stallion Cale's Helado Oro and buckskin dam Tostada Hidalgo.

These stallions will always pass on one of their Cream alleles to their offspring. This means that if you mate them to a bay mare, you will (mostly) get buckskins. We say ‘mostly’ because if the bay horse base coat color genotype is heterozygous for the MC1R gene (e.g., E/e), there is a 50% chance the offspring will be a palomino, and if you mate them to a chestnut (e/e), you will get a palomino.

The cremellos of our breed not only contribute to the maintenance and boost of the Pure Puerto Rican Paso Fino coat color spectrum but also eye color diversity. These cremellos have blue eyes primarily due to their genotype at the Cream locus. It is important to highlight that blue eyes have been observed on horses of all coat colors but are more prevalent and more likely to be inherited from double-dilute horses, such as cremellos, and genes that cause white, such as pintos. In our beloved Pure Puerto Rican Paso Finos, blue eyes have been observed in pintos, cremellos, and even bay horses. Interestingly, some of the bay horses with blue eyes have one of the two eyes affected. This phenomenon is called heterochromia.

Sueño de Paz (Ensueño Dorado x Platanera Dorada) is a cremello with blue eyes - Sueño de Paz sire and dam were both palominos. Therefore, he inherited one copy of the Cr from each parent to have a cremello phenotype. Sueño de Paz’s owner, Ms. Viveca Venegas Vilaró, kindly accepted our request for the genetic panels of her stallion and some of his offspring. His genetic panel confirms he is red-based (e/e) and homozygous for the Cream locus (Cr/Cr). He is also homozygous for the Agouti trait, but this trait is masked by the presence of two copies of the red factor (e/e). Given his homozygosity on the Cream locus, he can only produce buckskins or palominos when bred to a bay mare or palominos when bred to a chestnut mare. When bred to a palomino, Sueño de Paz offers a 50% chance of producing a cremello. When bred to a chestnut mare, he produces 100% palominos.

Interestingly, Sueño de Paz is a carrier of the tiger eye allele 2. Therefore, this outstanding cremello Pure Puerto Rican Paso Fino horse not only can produce palominos and buckskins, but can also help increase the number of Pure Puerto Rican Paso Finos with tiger eyes if bred to a carrier or tiger-eye mare. From the data shared by Ms. Venegas Vilaró, Sueño de Paz, has already produced offspring with tiger eyes. Here are some examples of his offspring (genetic panel information was confirmed):

1- Compositora de Sueños (Sueño de Paz x Sara de Plebeyo*) - Palomino mare with tiger eyes.

2- Cantares de Nan (Sueño de Paz x Sara de Plebeyo*) - Buckskin mare with tiger eyes.

*Sara de Plebeyo (Plebeyo x Sarita M.) - Is a bay mare heterozygous for the red factor (Ee). Therefore, she has a chance of producing 50% palominos and 50% buckskins when bred to Sueño de Paz.

The versatility of the Puerto Rican Paso Fino is one of the key features of the breed. While we often focus on what they can do in terms of riding and intelligence, we must not neglect to recognize the brilliant diversity of color that also contributes to the uniqueness of the breed. Preserving color while maintaining the important aspects of the Puerto Rican Paso Fino—gait, conformation, intelligence—is an important task to take accountability for and continue. We must not forget that the tiger eye is one of the defining features of the breed that can genetically show the Puerto Rican Paso Fino is different from other similarly gaited breeds. The tiger eye indicates that our breed has been bred separately from other populations, creating a unique breed in need of conservation.

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PLEASE SEE THE TABLE IN THE ACCOMPANYING PHOTOS

Table 1. Summary of the genotype and corresponding phenotype for some of the colors observed in the Puerto Rican Paso Fino.

Disclaimer: This table is not comprehensive and does not include the different color subtypes described in horses of our breed.

*N= normal/wild-type allele

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Acknowledgments:

We want to thank Viveca Venegas Vilaró, who collaborated with us to make this article possible.

References:

1- Rieder, S., Taourit, S., Mariat, D. et al. Mutations in the agouti (ASIP), the extension (MC1R), and the brown (TYRP1) loci and their association to coat color phenotypes in horses. Equus caballus. 12, 450–455 (2001).
2- UC Davis website (Bay, black and chestnut horses): https://vgl.ucdavis.edu/test/agouti-horse, https://vgl.ucdavis.edu/test/red-factor-horse
3- Book- Horse Genetics, 3rd edition | Drs. Ernest Bailey and Samantha Brooks | Wallingford, Oxfordshire, UK; Boston; CABI [2020].
4- Hauswirth R, Jude R, Haase B, Bellone RR, Archer S, Holl H, Brooks SA, Tozaki T, Penedo MC, Rieder S, Leeb T. Novel variants in the KIT and PAX3 genes in horses with white-spotted coat color phenotypes. Anim Genet. 44(6):763-5 (2013).
5- Curik I, Druml T, Seltenhammer M, Sundström E, Pielberg GR, Andersson L, Sölkner J. Complex inheritance of melanoma and pigmentation of coat and skin in Grey horses. PLoS Genet. 9(2):e1003248 (2013).
6- UC Davis website (Grey Horses): https://vgl.ucdavis.edu/test/gray
7- Yi Z, Gao Y, Yu F, Zhu Y, Liu H, Li J, Murua Escobar H. Interventions for treatment of cutaneous melanoma in horses: a structured literature review. Vet Res Commun. (2022).
8- Brooks SA, Lear TL, Adelson DL, Bailey E. A chromosome inversion near the KIT gene and the Tobiano spotting pattern in horses. Cytogenet Genome Res. 119(3-4):225-30 (2007).
9- Mariat D, Taourit S, Guérin G. A mutation in the MATP gene causes the cream coat color in the horse. Genet Sel Evol. 35(1):119-33 (2003).
10- Locke MM, Ruth LS, Millon LV, Penedo MC, Murray JD, Bowling AT. The cream dilution gene, responsible for the palomino and buckskin coat colors, maps to horse chromosome 21. Anim Genet. 32(6):340-3 (2001).
11- White, D., Rabago-Smith, M. Genotype–phenotype associations and human eye color. J Hum Genet 56, 5–7 (2011).

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The Pure Puerto Rican Paso Fino is an endangered breed of horse as recognized by The Livestock Conservancy and Equus Survival Trust.

is a free digital publication dedicated to promoting the Pure Puerto Rican Paso Fino Horse Breed in the United States.

Read the Versatility Issue at https://issuu.com/borntogait/docs/fall_2023

Subscribe at https://mailchi.mp/801e14b3d828/borntogait-subscribe

07/10/2023

ABOUT THE PINTO PATTERNS IN THE PUERTO RICAN PASO FINO

Stefanie Schermerhorn | Born to Gait Magazine (Fall 2023 Issue)

The origins of the Paso Fino have been written and rewritten for hundreds of years. From the landing of ships to the selective breeding and development of a breed. The breed we now know as the Paso Fino started with available stock and were animals of necessity. It would be hundreds of years before selective breeding would evolve into the modern breed for modern uses. Selective breeding would take many directions; varied purposes and preferences of people. Records and historical stories were passed down from breeders and family members. Farm to farm, region by region. Later farm and family records were written and shared. Eventually, breed associations were developed to maintain pedigrees. Simply the details which would become history were in the hands of people who were developing the breed in the direction they desired. At times, information was lost, omitted or altered and the narrative changed. This is common in many breeds, human intervention is frequently responsible for dramatic changes in a breed.

The near loss of “pinto” genetics in the modern Paso Fino is an example of human intervention. Over time, Paso Finos with pinto patterns, excessive markings and “high white” were eliminated from competition, then eliminated from registration within some associations. We often hear that pinto markings were signs of impurity, but history provides documentation that horses of color arrived as early as the Cortez ships. Museum archives of ships' logs describe what was loaded on the ships, and included color and markings of livestock. On one ship alone, three horses are described to have spotted body markings, and another 2 with excessive face and leg markings. We now know scientifically that excessive white and pintos’ patterns are controlled by a number of genetic markers, not a single “gene” from limited breeds that would prove impurity. Some of the spotting genes are dominant, others recessive but each is passed generation after generation, making the argument that these colorful horses are very likely descendants from the original “spotted” stock that landed and would become part of the gene pool that influenced the contemporary Paso Fino.

There are decades of photos and paintings of colorful Paso Finos. Paso Fino Registries have recorded horses with tobiano and sabino markings as far back as the 1920s, champions with pinto markings are recorded in the 1940s. These animals often had both solid and pinto offspring who continued to be included in registries and were used for breeding and competition.

At some point, the “traditional” Paso Fino description and preference became a solid-colored horse with no excessive white. At first, this preference was seen in the show ring, not much later some associations refused registration to pintos.

By the mid-1940s American servicemen stationed in Puerto Rico discovered the smooth-riding Paso Fino. They grew to not only admire the breed for its smooth ride and versatility, but for some discovering pinto-marked horses in the breed was an additional quality. There is no doubt of the fascination for loud color that North Americans have when it comes to their horses. Servicemen recognized that the Paso Fino was unlike any other riding horse that existed back home, so upon returning home to the States after WWII, several servicemen began to export Paso Finos from Puerto Rico. Horses of all colors including tobiano and sabino pintos were sent stateside, and from that, eventually, a group of owners banded together to form the first Paso Fino association in the USA in 1964. Pinto Paso Finos originating from Puerto Rico were among those that were registered in the early years. Some had been registered in Puerto Rico, others were offspring of horses that were from registered stock. And some were from stock that had been denied registration during the rule excluding excessive white.

More recently in Puerto Rico there was a resurgence of acceptance of horses that displayed loud white speckling markings (belly spots, tall stockings over knees and hock extending into frothy patterns towards hips). These markings are indicative of the sabino pinto pattern. For a period of time, this resulted in increased breeding and more sabino pintos being produced. In reviewing registrations and information on these horses, not one was described as a “pinto”. Science had already advanced with genetic testing, it would not be long until the sabino gene (sb1) would be identified and testable, but color testing is not something many Paso Fino breeders utilized at the time, or even today. Unfortunately, a number of horses from this line have been lost and very few descendants are producing colorful offspring.

While there are associations that now allow registration of tobianos, the number of years disallowing registration means that previous modern generations were not registered, or genetically tested so their offspring do not qualify for registration now. Horses with sabino or other white spotting patterns are registerable, but are not indicated as pinto.

If the bloodlines and the pinto patterns that exist in the breed are to be preserved there needs to be a concerted effort by those interested to work together, genetics tells us that having only one pedigree of specific attributes will not create a wide enough gene pool to lead to conservation. Owners and breeders will have to get involved with genetic testing and associations must work diligently to improve accurate descriptions based on genetic results.

To date, genetic testing has identified the tobiano, sabino and W20 genes within the Paso Fino breed. W20 which is considered a booster and can be responsible for expressions of typical markings. There are currently two horses identified with sabino-like patterns that have been tested for all patterns and are thought to be carrying a currently unidentified W pattern. With the discovery of more patterns, the breeders will test these horses again.

Pinto definition – Alternating patches of white and any other equine coat color appearing in random shapes and sizes. It is a generic term, not a singular gene.

Tobiano (TO)
Tobiano is a dominant gene, which means that it requires only one tobiano gene from one parent to express itself - this would be the heterozygous form of tobiano. A heterozygous tobiano has a 50% chance of passing the tobiano pattern to any of its offspring. The homozygous form of tobiano (requiring one tobiano gene from EACH parent) means that the probability of a horse passing on the tobiano pattern to all of its offspring is 100%. There is no lethal homozygous form of tobiano. Breeding of two tobiano horses can produce tobiano (Tt) (heterozygous - one parent passed tobiano gene) 50% of the time, tobiano (TT) (homozygous - both parents passed the tobiano gene) 25% of the time, and SOLID (no tobiano pattern from either parent) 25% of the time.

Sabino (SB1)
Sabino is an incomplete dominant gene. This means that only one copy from one parent is needed to express itself, but two copies will result in a different phenotype (appearance). The homozygous form of sabino will result in a horse that is white or nearly white from birth. Unlike Overo (a gene not found in the Paso Fino breed) and some White spotting genes, there is no lethal form of sabino.

Dominant White 20 (W20)
W20 is a dominant gene. This mutation is thought to have a more minor effect on protein function as well as a subtler effect on the amount of white expressed unless in combination with other dominant white alleles (and perhaps other white spotting genes). In combination with other white pattern alleles, W20 has been shown to increase the amount of white patterning, producing an all-white or nearly all-white phenotype.

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The Pure Puerto Rican Paso Fino is an endangered breed of horse as recognized by The Livestock Conservancy and Equus Survival Trust.

is a free digital publication dedicated to promoting the Pure Puerto Rican Paso Fino Horse Breed in the United States.

Read the Versatility Issue at https://issuu.com/borntogait/docs/fall_2023

Subscribe at https://mailchi.mp/801e14b3d828/borntogait-subscribe