Scientists at the Centre for GeoGenetics at the Natural History Museum of Denmark (University of Copenhagen) have sequenced the so far oldest genome from a prehistoric creature. They have done so by sequencing and analyzing short pieces of DNA molecules……Continue to A 700,000 year old horse gets its genome sequenced
A pintaloosa is a color breed that is the combination of Appaloosa and Pinto spotting patterns on the same horse. This combination is rare, but does occur from time to time on Mustangs, and occasionally in domestic horses. They can……Continue to International Pattern Spot Horse Registry (The Pintaloosa)
Bay and Brown are actually a modification of Black. In other words, bays and browns are black horses with a dominant modifying gene called AGOUTI added.
Agouti acts to restrict the black of the black horse to just specific points, which are the mane, tail and lower legs. This allows the red that is "uncovered" by agouti to show through on the body of the horse in varying degrees, depending on the type of Agouti present.
Chestnuts can carry agouti, but it won't show on them as they have no black hair to restrict to the points. They can, of course, pass it on to their offspring.
A black and chestnut cross might produce a bay foal. This happened because the agouti, or bay gene, actually came from the chestnut parent, and the black base color came from the black parent.
It is theorized that there are three different types of agouti. The Agouti which causes "regular" bay is written as an "A." The "wild type" Agouti, which results in a light bay horse with very little black on the legs, (usually just around the fetlocks) is written as "A+."Brown, or what is sometimes called "seal brown," (a nearly black horse with reddish areas on the muzzle and flanks) is written "At."
A horse will have some combination of the three types, one of the three types plus one non-agouti gene (one non-agouti gene is written as "a"), or have no agouti at all (written as "aa").
This is a theoretic genetic formula for how the dominant curly gene, the straight haired gene, and the recessive curly gene appear to interact. At the moment this is the best explanation we have that fits all the information we have. We do not yet have a DNA test for any "curly gene."
First, for a basic explanation of genetics, adapted from the UC Davis website:
In every living being, millions of instructions called
Every cell contains two copies of each gene, one contributed at conception by the mother and one by the father. The gene sets contain similar, but not necessarily identical, information in each gene. For example, both genes in a set may contain instructions that determine hair structure, but one gene may contain the instructions for straight hair and the other for curly hair.
The alternative forms of each gene are called alleles.
If both alleles are identical, then the individual is Homozygous at that gene locus (location). If the alleles are dissimilar, then the individual is said to be Heterozygous for that gene set. Information about the homozygosity or heterozygosity for various genes can be inferred from information about parents and/or progeny and can be used for predicting the outcome of matings.
Often when the gene pair is heterozygous, one allele may be visibly expressed but the other is not. The expressed allele in a heterozygous pair is known as the Dominant allele and the unexpressed one as the Recessive allele. The term dominant is given an allele only to describe its relationship to related alleles, and is not to be taken as an indication of any kind of physical or temperamental strength of the allele or the individual possessing it. Likewise, possession of a recessive allele does not connote weakness.
In any individual expressing the dominant allele of a gene, it cannot be determined by looking at the individual whether the second allele is a dominant or recessive. The presence of a recessive allele may be masked by a dominant allele, which leads to the expression Hidden Recessive. A dominant alleles is never hidden by it.s recessive allele.
For simplicity in constructing models, geneticists symbolize genes by letters such as A, B, C and so on. A dominant allele of a gene can be symbolized by an italicized capital letter, e.g., A, and the recessive by an italicized lower case letter, e.g. a...
CC RR - Homozygous dominant curly, looks curly, always throws dominant curly foals. Has normal straight genes at recessive loci.
Cc RR - Heterozygous dominant curly, looks curly, has normal straight genes at recessive loci. Throws curly gene 50% of time.
CC Rr - Homozygous dominant, heterozygous recessive. Looks like a curly, can throw recessive curly if bred to another recessive carrier or recessive curly 50% of the time. Won't be able to tell when since all foals will be curly due to 100% transmission of a dominant curly gene.
Cc Rr - Heterozygous dominant and heterozygous recessive. Is dominant curly visibly, and can produce dominant curly foals off straight mares 50% of the time and can transmit recessive gene 50% of the time.
CC rr - Homozygous dominant & homozygous recessive. Curly coat. Will always throw curly foals and will always transmit one recessive curly gene.
Cc rr - Heterozygous dominant curly and homozygous recessive curly. Always curly coated, and always transmits a recessive gene, but only throws dominant gene 50% of the time, so can throw straights off non recessive curlies, or straight horses.
cc RR - Normal straight horse. No curly signs visible. Don't know about hypoallergenicity. Can't throw any curly gene.
cc Rr - Straight coated horse. Carries one recessive gene. If paired with a recessive curly or recessive curly carrier can throw a curly.
cc rr - Recessive curly. No dominant Curly gene, but two recessive curly ones. Will always throw a recessive curly gene, but will only parent a curly if the other parent also throws in a recessive curly gene.
There are six basic color patterns in the Appaloosa horse, and endless variations. Appaloosas are best known for their spots, but they have many variations in coat colors. The appy is a very versatile breed that has many desirable qualities.…Continue to Appaloosa Horse
There are several genetic diseases of concern to Akhal-Teke breeders. The genetic diversity of the breed is relatively low with an AVK of 30-50%, which raises concerns for dealing with an increase in carriers of these conditions, and even some risk of inbreeding depression. To date, there are no DNA tests for these conditions.
Naked Foal Syndrome or Hairless Foal Syndrome is most likely an autosomal, lethal recessive gene, though the exact inheritance pattern has not yet been verified. It appears to be similar in clinical signs, though not identical to junctional epidermolysis bullosa (JEB) found in the Belgian horse and another condition of a similar nature identified in the American Saddlebred.
The defect causes foals to be born without any hair coat, mane or tail. In some cases, the front teeth are in at birth or molars grow abnormally from normal jaws. Other symptoms include persistent diarrhea, frequent digestive disorders and laminitis-like, treatment-resistant rotation of the coffin bones in the hooves.
Due the lack of normal skin protection, secondary symptoms include scaly, dry and inflamed skin, as well as severe cases of sunburn in summer and frequent pulmonary infections during winter. NFS is always fatal, most foals die within weeks of birth, although some horses have survived up to the age of two years.
Early demise is usually caused by digestive problems, whereas older horses need to be humanely euthanized because of severe laminitis-induced pain. Cases were recorded within the Akhal-Teke breed as early as 1938. In spite of the breed's limited population, naked foals have been born in every country in which the breed is represented, including the USA.
Some 35 carriers have been ascertained, including 943 Arslan, 736 Keymir, 2001 Mariula or 1054 Gilkuyruk, but the estimated number of unknown cases is very likely much higher, as several Russian and Turkmenian breeders have acknowledged that many NFS foals are often just reported as stillborn or aborted.
Hereditary cryptorchidism is very common within the Akhal-Teke breed and many cases exist where afflicted stallions can be traced through multiple generations. The influential foundation sire, 2a Boinou, was a cryptorchid according to experts of the breed. Other verified cryptorchids include 779 Peren, 1248 Orlan, 971 Khalif, and Garayusup. 1069 Kortik produced three cryptorchid sons. Unlike most European and many North American breed organisations, neither Russia nor Turkmenistan bar cryptorchids from breeding. Cryptorchidism is said to be related to health and character problems, such as testicular cancer and malignant behaviour. Affected horses cause significantly higher costs when castrated.
Wobbler syndrome, seen in a number of breeds, including the Thoroughbred, is thought to be on the increase in the Akhal-Teke. Of particular concern is the form known as cervical vertebral malformation (CVM), which may also be linked to Osteochondritis dissecans (OCD) to a certain extent. There is a genetic component to Wobbler's, but factors such as breeding Akhal-Teke horses for certain conformation in the neck and management of young stock for forced growth and greater size may also play a role.
The Akhal-Teke is one of several breeds that is prone to degenerative suspensory ligament desmitis (DSLD) Some animals also have a condition known as "Kissing Spine."
Often called a chocolate palomino, this coloring is actually a Silver Dapple--a true black horse with a modifying gene (Z). The Silver Dapple gene turns the black hairs of the mane and tail to a silvery white, and the body color to a chocolate. A true chocolate palomino is a liver chestnut with a Cream gene. (ee, Cr).
This Gypsy Vanner mare shows the more typical dappling of this color. She is Lady Godiva, imported and owned by Mulberry Lane Farms
