Sheep-goat hybrid
Encyclopedia
A sheep–goat hybrid is the hybrid offspring of a sheep and a goat
. Although sheep and goats seem similar and can be mated, they belong to different genera in the subfamily Caprinae of the family Bovid
ae. Sheep belong to the genus Ovis
and have 54 chromosomes, while goats belong to the genus Capra
and have 60 chromosomes. The offspring of a sheep-goat pairing is generally stillborn. Despite widespread shared pasturing of goats and sheep, hybrids are poorly attested, indicating the genetic distance between the two species. They are not to be confused with geep, which are chimerae
.
Ministry of Agriculture in 2000, a male sheep impregnated a female goat resulting in a live offspring. This hybrid had 57 chromosomes, intermediate between sheep (54) and goats (60) and was intermediate between the two parent species in type. It had a coarse outer coat, a woolly inner coat, long goat-like legs and a heavy sheep-like body. Although infertile, the hybrid had a very active libido, mounting both ewes and does even when they were not in heat. He was castrated when he was 10 months old, as were the other kids and lambs in the herd.
A male sheep impregnated a female goat in New Zealand resulting in a mixed litter of kids and a female sheep-goat hybrid with 57 chromosomes. The hybrid was subsequently shown to be fertile when mated with a ram. In France natural mating of a doe with a ram produced a female hybrid carrying 57 chromosomes. This animal backcrossed in the veterinary college of Nantes
to a ram delivered a stillborn and a living male offspring with 54 chromosomes.
wrote:
Supposedly, most sheep–goat hybrids die as embryos. Hybrid male mammals are often sterile due to a phenomenon called Haldane's rule
. The Haldane phenomenon may apply even when the parent species have the same number of chromosomes, as in most cat-species hybrids. It sometimes does not apply when the species chromosome number is different, as in wild horse (chromosome number = 66) with domestic horse (chromosome number = 64) hybrids. Hybrid female fertility tends to decrease with increasing divergence in chromosome similarity between parent species. Presumably, this is due to mismatch problems during meiosis
and the resulting production of eggs with unbalanced genetic complements.
Goat
The domestic goat is a subspecies of goat domesticated from the wild goat of southwest Asia and Eastern Europe. The goat is a member of the Bovidae family and is closely related to the sheep as both are in the goat-antelope subfamily Caprinae. There are over three hundred distinct breeds of...
. Although sheep and goats seem similar and can be mated, they belong to different genera in the subfamily Caprinae of the family Bovid
Bovid
A bovid is any of almost 140 species of cloven-hoofed ruminant mammal at least the males of which bear characteristic unbranching horns covered in a permanent sheath of keratin....
ae. Sheep belong to the genus Ovis
Ovis
Ovis is a genus of mammals, part of the goat-antelope subfamily of the ruminant family Bovidae. Its five or more highly gregarious species are known as sheep...
and have 54 chromosomes, while goats belong to the genus Capra
Capra (genus)
Capra is a genus of mammals, the goats or wild goats, composed of up to nine species including the wild goat, the markhor and several species known as ibex....
and have 60 chromosomes. The offspring of a sheep-goat pairing is generally stillborn. Despite widespread shared pasturing of goats and sheep, hybrids are poorly attested, indicating the genetic distance between the two species. They are not to be confused with geep, which are chimerae
Chimera (genetics)
A chimera or chimaera is a single organism that is composed of two or more different populations of genetically distinct cells that originated from different zygotes involved in sexual reproduction. If the different cells have emerged from the same zygote, the organism is called a mosaic...
.
Cases
At the BotswanaBotswana
Botswana, officially the Republic of Botswana , is a landlocked country located in Southern Africa. The citizens are referred to as "Batswana" . Formerly the British protectorate of Bechuanaland, Botswana adopted its new name after becoming independent within the Commonwealth on 30 September 1966...
Ministry of Agriculture in 2000, a male sheep impregnated a female goat resulting in a live offspring. This hybrid had 57 chromosomes, intermediate between sheep (54) and goats (60) and was intermediate between the two parent species in type. It had a coarse outer coat, a woolly inner coat, long goat-like legs and a heavy sheep-like body. Although infertile, the hybrid had a very active libido, mounting both ewes and does even when they were not in heat. He was castrated when he was 10 months old, as were the other kids and lambs in the herd.
A male sheep impregnated a female goat in New Zealand resulting in a mixed litter of kids and a female sheep-goat hybrid with 57 chromosomes. The hybrid was subsequently shown to be fertile when mated with a ram. In France natural mating of a doe with a ram produced a female hybrid carrying 57 chromosomes. This animal backcrossed in the veterinary college of Nantes
Nantes
Nantes is a city in western France, located on the Loire River, from the Atlantic coast. The city is the 6th largest in France, while its metropolitan area ranks 8th with over 800,000 inhabitants....
to a ram delivered a stillborn and a living male offspring with 54 chromosomes.
Characteristics
There is a long-standing belief in sheep–goat hybrids, which is presumably due to the animals' resemblance to each other. Some primitive varieties of sheep may be misidentified as goats. In Darwinism – An Exposition Of The Theory Of Natural Selection With Some Of Its Applications (1889), Alfred Russel WallaceAlfred Russel Wallace
Alfred Russel Wallace, OM, FRS was a British naturalist, explorer, geographer, anthropologist and biologist...
wrote:
[...] the following statement of Mr. Low: "It has been long known to shepherds, though questioned by naturalists, that the progeny of the cross between the sheep and goat is fertile. Breeds of this mixed race are numerous in the north of Europe." Nothing appears to be known of such hybrids either in Scandinavia or in Italy; but Professor Giglioli of Florence has kindly given me some useful references to works in which they are described. The following extract from his letter is very interesting: "I need not tell you that there being such hybrids is now generally accepted as a fact. BuffonGeorges-Louis Leclerc, Comte de BuffonGeorges-Louis Leclerc, Comte de Buffon was a French naturalist, mathematician, cosmologist, and encyclopedic author.His works influenced the next two generations of naturalists, including Jean-Baptiste Lamarck and Georges Cuvier...
(Supplements, tom. iii. p. 7, 1756) obtained one such hybrid in 1751 and eight in 1752. Sanson (La Culture, vol. vi. p. 372, 1865) mentions a case observed in the Vosges, France. Geoff. St. Hilaire (Hist. Nat. Gén. des reg. org., vol. iii. p. 163) was the first to mention, I believe, that in different parts of South America the ram is more usually crossed with the she-goat than the sheep with the he-goat. The well-known 'pellones' of Chile are produced by the second and third generation of such hybrids (Gay, 'Hist, de Chile,' vol. i. p. 466, Agriculture, 1862). Hybrids bred from goat and sheep are called 'chabin' in French, and 'cabruno' in Spanish. In Chile such hybrids are called 'carneros lanudos'; their breeding inter se appears to be not always successful, and often the original cross has to be recommenced to obtain the proportion of three-eighths of he-goat and five-eighths of sheep, or of three-eighths of ram and five-eighths of she-goat; such being the reputed best hybrids."
Supposedly, most sheep–goat hybrids die as embryos. Hybrid male mammals are often sterile due to a phenomenon called Haldane's rule
Haldane's rule
Haldane's rule or Haldane's law was formulated in 1922 by the British evolutionary biologist J.B.S. Haldane. It describes hybrid sterility in species and is extended to describe speciation in evolutionary theory, in two parts: the rule of hybrid sterility and the rule of hybrid inviability...
. The Haldane phenomenon may apply even when the parent species have the same number of chromosomes, as in most cat-species hybrids. It sometimes does not apply when the species chromosome number is different, as in wild horse (chromosome number = 66) with domestic horse (chromosome number = 64) hybrids. Hybrid female fertility tends to decrease with increasing divergence in chromosome similarity between parent species. Presumably, this is due to mismatch problems during meiosis
Meiosis
Meiosis is a special type of cell division necessary for sexual reproduction. The cells produced by meiosis are gametes or spores. The animals' gametes are called sperm and egg cells....
and the resulting production of eggs with unbalanced genetic complements.