Evolutionary biology and horses focus on the study of the evolutionary processes that have shaped the development, adaptation, and diversification of the Equus genus. This field examines the genetic, morphological, and ecological changes that have occurred over millions of years, leading to the modern horse. Researchers explore the transition from small, multi-toed ancestors to the large, single-toed horses of today, analyzing fossil records, genetic data, and environmental factors that influenced these changes. This page compiles peer-reviewed research studies and scholarly articles that investigate the evolutionary history, genetic adaptations, and ecological interactions of horses, providing insights into their development and survival strategies throughout history.
Skopakoff C.The development of the chewing, lacerative and omnivorous dentition type was confirmed on the base of the author's studies on the dentition of placentalia representatives. The use of vegetable food by the rodents and herbivorous mammals induces an efficient development of molars, absence or reduced number of incisors and canines of the upper jaw and increased number of incisors and absence of canines of the lower jaw, resulting into the proposal of an alteration of the dentition formula for rabbits and for the rest of the rodents (Simplicidentata), for herbivorous and for horses. In beasts of ...
Higuchi R, Bowman B, Freiberger M, Ryder OA, Wilson AC.To determine whether DNA survives and can be recovered from the remains of extinct creatures, we have examined dried muscle from a museum specimen of the quagga, a zebra-like species (Equus quagga) that became extinct in 1883 (ref. 1). We report that DNA was extracted from this tissue in amounts approaching 1% of that expected from fresh muscle, and that the DNA was of relatively low molecular weight. Among the many clones obtained from the quagga DNA, two containing pieces of mitochondrial DNA (mtDNA) were sequenced. These sequences, comprising 229 nucleotide pairs, differ by 12 base substitu...
Ralston SL.Members of the genus Equus are large, nonruminant herbivores. These animals utilize the products of both enzymatic digestion in the small intestine and bacterial fermentation (volatile fatty acids) in the cecum and large colon as sources of metabolizable energy. Equine animals rely primarily upon oropharyngeal and external stimuli to control the size and duration of an isolated meal. Meal frequency, however, is regulated by stimuli generated by the presence and (or) absorption of nutrients (sugars, fatty acids, protein) in both the large and small intestine plus metabolic cues reflecting body ...
Rubin CT, Lanyon LE.Galileo (1638) observed that "nature cannot grow a tree nor construct an animal beyond a certain size, while retaining the proportions which suffice in the case of a smaller structure". However, subsequent measurement has shown that limb bone dimensions are scaled geometrically with body size (Alexander et al., 1979a), and that the material properties of their constituent bone tissue are similar in animals over a wide range of body weight (Sedlin & Hirsch, 1966; Yamada, 1970; Burstein et al., 1972; Biewener, 1982). If, as suggested in previous scaling arguments (McMahon, 1973; Biewener, 19...
Bean WJ.The RNAs coding for the nucleoproteins of a panel of influenza isolates from human and nonhuman hosts were compared by RNA-RNA hybridization to determine the extent of genetic diversity of this protein and to determine if related nucleoproteins (NP) are consistently found in viruses from certain hosts. Five nucleoprotein groups were defined. Group 1 contains nearly all of the avian influenza viruses, group 2 includes only certain viruses isolated from gulls, group 3 includes all recent equine influenza strains, group 4 contains only equine/Prague/1/56, and group 5 contains all human and swine ...
Science (New York, N.Y.)June 24, 1983
Volume 220, Issue 4604 1403-1404 doi: 10.1126/science.220.4604.1403
Berger J.The identities, sexes, and reproductive status of groups of wild horses (Equus caballus) living in the Great Basin Desert of North America were known prior to their deaths on ridgelines. Another group of very young horses died on a quagmire. Snow accumulation or drought was apparently responsible for the mass deaths. These data have implications for reconstructing some aspects of the social structure of fossil mammals on the basis of skewed sex or age ratios in bone assemblages.
Berger J.Much evidence now suggests that the postnatal killing of young in primates and carnivores, and induced abortions in some rodents, are evolved traits exerting strong selective pressures on adult male and female behaviour. Among ungulates it is perplexing that either no species have developed convergent tactics or that these behaviours are not reported, especially as ungulates have social systems similar to those of members of the above groups. Only in captive horses (Equus caballus) has infant killing been reported. It has been estimated that 40,000 wild horses live in remote areas of the Great...
Colton SW, Downing DT.Skin surface lipids from Equus caballus, E. przewalskii, E. asinus, E. grevyi, E. hemionus onager and a mule (E. asinus/E. caballus) were analyzed in detail. In all species the surface lipid mixtures consisted of giant-ring lactones, cholesterol, cholesteryl esters and minor amounts of wax diesters. In E. caballus, the lactone hydroxyacids were entirely branched chained, while in E. asinus and E. grevyi they were almost exclusively straight chained. In E. przewalskii, the onager and the mule there were both straight and branched chain hydroxyacid lactones. These results are in harmony with pub...
Putt W, Whitehouse DB.This paper reports genetic variation at the prealbumin (Pr), postalbumin (Pa) and transferrin (Tf) loci in Equus przewalskii found using thin layer isoelectric focusing and an amphoteric separator. The method resolves all three loci plus serum esterase (Es) on a single gel, and typing of all four loci is readily achieved. In addition to the esterase alleles previously reported by Fisher & Scott (1979), five alleles were found at the Pr locus, three at the Pa locus and six at the Tf locus. Analysis of several mating types confirms inheritance is autosomal and codominant for all four loci.
Poskus E, Peña C, Pérez AR, Vita N, Heinrich JJ, Paladini AC.The immunological behavior of sera from hypopituitary patients treated with human GH (hGH) has been studied by homologous and heterologous RIAs using 125I-labeled hormones. Along with antibodies against hGH, antibodies exhibiting antibovine and antiequine GH (anti-bGH and anti-eGH, respectively) activities were also found. Displacement experiments showed that hGH was an effective competitor of 125 I-labeled hGH, whereas bGH and eGH were quite inefficient. Conversely, when the tracer was 125I-labeled bGH, both bGH and eGH were good displacers, while the human hormone was poor. The values of the...
Klingel H.The basic social unit in feral horses is the family group consisting of one stallion, one to a few unrelated mares and their foals. Surplus stallions associate in bachelor groups. Stallions are instrumental in bringing mares together in a unit which then persists even without a stallion. The similarity of social organization in populations living in a variety of different habitats indicates that feral horses have reverted to the habits of their wild ancestors, and that domestication has had no influence on this basic behavioural feature.
Rowlands IW.The world-wide foaling rate in the mare is low and in the Hannoverian breed has remained asymptotic at about 50 per cent for over 150 years. In an attempt to discover some of the possible reasons for this low fertility rate, the evolutionary history of the perissodactyls, the odd-toed ungulates, is reviewed here. Of the 156 genera of this order, 152 are in the fossil record; this gives them the highest extermination rate of all the mammal groups. Some of the unusual and unique features of the reproductive physiology of the mare and their possible association with low fertility are considered.
Hatami-Monazah H, Pandit RV.The group of Caspian ponies studied contained some animals with 65 chromosomes and others with 64 chromosomes. The morphology and G-banding pattern of the chromosomes resembled those of Equus caballus and E. przewalskii. The karyogram of animals with 65 chromosomes was identical to that of the cross between E. caballus and E. przewalskii. It is suggested that the Caspian pony is the product of natural hybridization between E. caballus and E. prezwalskii. Low reproductive effeciency of the Caspian pony is suggested as the cause of decline in the population of these animals.
Weitkamp LR, Allen PZ.Ancient origin of the equine vitamin D binding protein (Gc) polymorphism is suggested by the finding of two alleles, Gc(F) and Gc(S), in each of three equine subgenera, Equus, Asinus and Hippotigris. The equine Gc and albumin loci are closely linked (lod score = 6). Although no recombinants were observed, the data are not inconsistent with a map distance similar to the 2 centimorgans reported for the human albumin/Gc linkage relationship. Gametic association between the Gc(F) and Alb(F) alleles appears probable in the American Standardbred horse, perhaps as a result of population structure. Si...
Science (New York, N.Y.)November 5, 1976
Volume 194, Issue 4265 626-627 doi: 10.1126/science.790567
Radinsky L.Previous interpretations of early horse brains were based on an incorrectly identified fossil endocast, now believed to be from a condylarth. Newly prepared endocasts of Hyracotherium, the oldest horse and one of the earliest perissodactyls, reveal a relatively larger brain, with a more expanded neocortex, than existed in the condylarth ancestors of perissodactyls. Fifty million years ago, horse brains had suprasylvian, ectolateral, and lateral sulci, but the frontal lobe was undeveloped.
Ambler RP, Meyer TE, Kamen MD.The amino-acid sequences of the cytochromes c2 from the photosynthetic non-sulfur purple bacteria Rhodomicrobium vannielii and Rhodopseudomonas viridis have been determined. Only a single residue deletion (at position 11 in horse cytochrome c) is necessary to align the sequences with those of mitochondrial cytochromes c. The overall sequence similarity between these cytochromes c2 and mitochondrial cytochromes c is closer than that between mitochondrial cytochromes c and the other cytochromes c2 of known sequence, and in the latter multiple insertions and deletions must be postulated before a ...
Harris DT, Camenisch TD, Jaso-Friedmann L, Evans DL.Natural killer (NK) cells are large granular lymphocytes that lyse a wide variety of transformed and virally-infected target cells without prior exposure to antigen, and without restriction by major histocompatibility complex antigens. Although NK cells have been identified in a variety of mammalian species, how NK cells recognize antigen and trigger lysis is unknown. Recently, monoclonal antibodies made against NK-like cells from teleost fish were shown to react with NK cells from humans and rats, and to inhibit their cytolytic activity. The role of this apparently evolutionarily conserved fu...
Murata T, Yamashiro Y, Kondo T, Nakaichi M, Une S, Taura Y.Complementary DNA (cDNA) for bovine quaking gene (Bqk), equine quaking gene (Eqk) and porcine quaking gene (Pqk), which are homologous to mouse quaking gene (qkI), were isolated, and their nucleotide sequences were determined. cDNA sequences of Bqk, Eqk and Pqk showed very high homology to that of qkI at nucleotide level; 94.2, 95.7 and 95.6%, respectively. Deduced amino acid sequences for Bqk, Eqk and Pqk perfectly matched to that of qkI. These findings suggest that the quaking gene family is highly conserved during mammalian evolution, and that Bqk, Eqk and Pqk are likely to have important b...
Díaz S, Dulout FN, Peral-García P.Genetic polymorphism was analyzed for five blood proteins: albumin - Al, esterase - Es, alpha(1)B-glycoprotein - Xk, transferrin - Tf and hemoglobin - Hb in 200 Thoroughbred (TB) and 124 Argentine Creole (AC) horses. Of the five systems examined, Tf and Hb were not in Hardy-Weinberg equilibrium in either breed and Es was not in equilibrium in the Creole breed. Genetic variability, estimated as average heterozygosity, was higher in AC (H = 0.585 +/- 0.131) than in TB (H = 0.353 +/- 0.065). The genetic differentiation between these two populations (F(ST)) was 0.109. Thus, of the total genetic di...
Kantanen J.Domestic animal production in the arctic region is often thought to be based exclusively on reindeer herding. There are, however, regions in Northern Europe and Siberia having a long tradition in rearing breeds of cattle and horse adapted to the northers conditions also. The development of these arctic animal breeds has been largely founded on old tradition rather than on the programs of breeding organizations. As a result of the selection carried out by nature and man, the domestic animals of arctic regions express characteristics that are metabolic, structural, associated with reproductive p...
Nasir L, Reid SW.The evolutionary conserved region of the equine homologue of the p53 gene from the donkey genome was PCR amplified and cloned. The 1380 bp fragment consisted of exons 5 to 9 and the intervening introns. The exonic and intronic DNA sequences showed a variable but high level of homology with previously published human sequences. The aminoacid sequences corresponding to the evolutionary conserved domains II, III, and V were identical to the human regions, whilst domain IV was 96% homologous.
MacLaren JA.Locomotion in terrestrial tetrapods is reliant on interactions between distal limb bones (e.g. metapodials and phalanges). The metapodial-phalangeal joint in horse (Equidae) limbs is highly specialized, facilitating vital functions (shock absorption; elastic recoil). While joint shape has changed throughout horse evolution, potential drivers of these modifications have not been quantitatively assessed. Here, I examine the morphology of the forelimb metacarpophalangeal (MCP) joint of horses and their extinct kin (palaeotheres) using geometric morphometrics and disparity analyses, within a phylo...
Nishita Y, Amaike Y, Spassov N, Hristova L, Kostov D, Vladova D, Peeva S, Raichev E, Vlaeva R, Masuda R.The domestication of the horse began possibly more than 5000 years ago in the western part of the Eurasian steppe, and according to the leading hypothesis, horses first spread from the Steppe toward the region of the Thracian culture, starting in the second half of the 2nd millennium BCE and flourished from the fifth to first centuries BCE, mainly located in present-day Bulgaria. We analyzed 17 horse bone remains excavated from Thracian archaeological sites (fourth to first centuries BCE) in Bulgaria and successfully identified 17 sequences representing 14 different haplotypes of the mitocho...
Salamanca-Carreño A, Parés-Casanova PM, Monroy-Ochoa NI, Vélez-Terranova M.This study examined paedomorphosis in PAH and F1 crossbreds. A sample of 99 horses was selected from 40 different breeders and consisted of three groups: stallions ( = 16), mares ( = 53), and geldings ( = 30), ranging from 10 months to 27 years in age. All horses presented a concave celloid lateral left head profile in the acquired photographic images. The hypothesis proposed in this study suggested the lateral profile of the head in juveniles was representational in the adult form due to the neonate's facial bones (part of the splanchnocranium) developing at a different rate to those of the s...
Salamanca-Carreño A, Parés-Casanova PM, Crosby-Granados RA, Vélez-Terranova M, Bentez-Molano J.The skull is divided into neurocranium and splanchnocranium, and its variation allows ecomorphological studies to learn about possible evolutionary and adaptive characteristics. The basicranial organization of the neurocranium and splanchnocranium modules was studied in a sample of 31 skulls from adult Araucanian horses by means of 2D geometric morphometric techniques. The neurocranium and splanchnocranium modules on the ventral aspect were analyzed separately using a set of 31 landmarks. The RV coefficient (the multivariate analog of a correlation) was estimated to analyze the independence of...
May-Davis S, Vermeulen Z, Hunter R, Brown W.For over 200 years, equine anatomic literature has chiefly portrayed the attachment points of the nuchal ligament lamellae (NLL) from the second to the seventh cervical vertebrae (C2-C7). However, recent studies have shown that the modern domestic horse, Equus caballus, primarily exhibits the attachments points from C2-C5. Here we present the rare finding of a complete NLL attached from C2-C7 in one Australian Stock Horse (ASH) and discuss the potential implications of these findings. Previously, this trait has only been confirmed among close descendants of Equus ferus ferus; namely the primi...
Riggenbach Ch, Stranzinger G, Poncet PA, Glowatzki ML, Muntwyler J, Gaillard C, Rieder S.In this study it was investigated whether the "Einsiedler" warmblood horse, a historically old horse population from central Switzerland (Abbey of Einsiedeln), is distinguishable from micellaneous horse breeds, using molecular genetic techniques. The breeding history of Einsiedler horses is characterised by systematic line breeding through the dams. Therefore, two Einsiedler dam lines (N = 28), going back to the middle of the 19th century according to pedigree entries, were the focus of the survey. Random samples of diverse warmblood horse populations, but also samples from more distinct types...
Kalmykov NP.This report analyzes a find of fossils of Pliocene three-toed horse (Hipparion tchicoicum) in western Transbaikalia. The age of the mammalian fauna from red-brown clay in the Udunga locality indicates that Chikoi hipparion lived in the south of Eastern Siberia as early as the second half of the Early Pliocene; its remains in this area were known only from the red beds of the Upper Pliocene. This find made it possible to fill the existing hiatus (Early Pliocene) in its stratigraphic distribution: Late Miocene-Late Pliocene. The range of this three-toed horse species did not go beyond the border...
Dubrovskaia RM, Starodumov IM, Bannikova LV.The estimation of genetic differentiation between 27 horses breeds originated in USSR, based on serum proteins polymorphism (loci Tf, Al, Es) is shown. Genetical variability among aborigine breeds is higher then among cultural ones. The erosion of gene pool of Przewalski's Horse is explained by special history of this population and a few horses in analyzing group. Genetic distances reflect the directions and intensity of breeding. High genetical distances between Przewalski's Horse, Shetland Pony and other horses obtained could be explained by overcoming the "bottle neck" of selections in bre...
Parés-Casanova PM.Morphological integration and modularity are concepts that refer to the covariation level between the components of a structure. Morphological modules are independent subsets of highly correlated traits. The horse skull has been studied as a whole functional structure for decades, but the integrative approach towards quantitative examination of modules is scarce. We report here the first evaluation of cranial modularity in the horse at basal level. For this, we studied the modularity hypothesis for splanchnocranium and basicranium modules in the horse, two phenotipic regions under local influe...
Kaaden OR, Truyen U.There is a continuous change in viral epidemics with respect to clinical symptoms, their duration or disappearance and the emergence of new diseases. This can be observed both in human and animal diseases. This evolution of virus diseases is mainly related to three factors: etiological agent, host and environment. As far as genetic alterations of the virus are concerned, two major mechanisms are involved: 1) mutations such as recombination and reassortment; 2) selection for resistance or susceptibility. The epidemiology of newly emerged virus diseases in man and animals, such as AIDS and hemor...
Ma L, Sang M, Zhang J, Zhang S.Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF superfamily and plays multifunctional roles in the immune system. In the present study, a homolog of TRAIL from the Mongolian horse (named ecTRAIL) was identified and characterized. The 870-bp open reading frame encodes a polypeptide of 289 amino acid residues with a predicted molecular weight of 33.47 kDa and pI of 8.47. The genomic structure of ecTRAIL shares a five-exon/six-intron arrangement similar to its orthologs. Multiple alignments show that ecTRAIL is a type II transmembrane protein with a t...
Miszczak F, Pronost S, Vabret A.Equine arteritis virus (EAV) is the causative agent of equine viral arteritis, a disease observed only in equids. EAV is the prototype of the family Arteriviridæ within the order Nidovirales. EAV is an enveloped, positive-sense, single-stranded RNA virus with a considerable variation in the genome as observed in other RNA viruses. During natural infections, EAV may cause abortion and persistent subclinical infections in stallions which can shed the virus in the semen for years, or even lifetime. Chronically infected stallions represent the natural reservoir of the virus. They ensure the persi...
Landry Z, Roloson MJ, Fraser D.The metapodials of extinct horses have long been regarded as one of the most useful skeletal elements to determine taxonomic identity. However, recent research on both extant and extinct horses has revealed the possibility for plasticity in metapodial morphology, leading to notable variability within taxa. This calls into question the reliability of metapodials in species identification, particularly for species identified from fragmentary remains. Here, we use ten measurements of metapodials from 203 specimens of four Pleistocene horse species from eastern Beringia to test whether there are s...
Kalmykov NP.The first data on polymorphism and preadaptation of the Pleistocene horses in the mountains surrounding Lake Baikal are presented. It has been shown that disregard of intraspecific polymorphism leads to unreasonable ignoring of their diversity, phylogenetically false constructions, and incorrect interpretation of natural environment.
León B, González G, Nicoli A, Rojas A, Pizio AD, Ramirez-Carvajal L, Jimenez C.Venezuelan Equine Encephalitis virus (VEEV) is an arboviral pathogen in tropical America that causes lethal encephalitis in horses and humans. VEEV is classified into six subtypes (I to VI). Subtype I viruses are divided into epizootic (IAB and IC) and endemic strains (ID and IE) that can produce outbreaks or sporadic diseases, respectively. The objective of this study was to reconstruct the phylogeny and the molecular clock of sequences of VEEV subtype I complex and identify mutations within sequences belonging to epizootic or enzootic subtypes focusing on a sequence isolated from a mare in C...
Ma Y.Equine rotavirus (ERV) strain L338 (G13P[18]) has a unique G and P genotype. However, the evolutionary relationship of L338 with other ERVs is still unknown. Here whole genome analysis of the L338 ERV strain was independently performed. Its genotype constellations were determined as G13-P[18]-I6-R9-C9-M6-A6-N9-T12-E14-H11, confirming previous genotype assignments. The L338 strain only shared the P[18] and I6 genotypes with other ERVs. The nucleotide sequences of the other 9 RNA segments were different from those of cogent genes of all other group A rotavirus (RVA) strains including ERVs and fo...
Chen J, Wang H, Li J, Liu S, Li B, Sun Y, Wang H, Manglai D.To date, the origins, domestication, and genetic structure of Chinese Mongolian horses (CMH) are poorly understood. Furthermore, there have been sparse reports on the genetic differences between CMH and Thoroughbred. In order to determine their genetic structure, understand their genetic relationships, and explore their domestication processes, we performed an extensive survey of creatine kinase (muscle isoenzyme; variations among six populations of indigenous CMH, cultivated Sanhe horses, and imported Thoroughbred. Twenty-three single-nucleotide polymorphisms were found among the 343 horse s...
Buff PR, Messer NT, Cogswell AM, Wilson DA, Johnson PJ, Keisler DH, Ganjam VK.Endocrine characteristics of Quarter Horse-type mares were determined during a 68 h feed deprivation and again in the same mares following surgical thyroidectomy (THX). A crossover experimental design was implemented, in which mares received brome hay available ad libitum (FED) or were food deprived (RES) for 68 h. Blood samples were collected every 20 min for 48 h, beginning 20 h after the onset of food deprivation. Concentrations of triiodothyronine and thyroxine were undetectable post-THX. Plasma concentrations of thyrotropin were greater post-THX versus pre-THX (P<0 x 001). Plasma conce...
Deriusheva SE, Loginova IuA, Chiriaeva OG, Iasinetskaia NI, Efimov AM.Restriction endonuclease in situ digestion of metaphase chromosomes gives an opportunity to reveal strips with different structure within GC-rich pericentric heterochromatin of the domestic horse and the wild Przewalski horse. Blocks of heterochromatin, which are insensitive to HaeIII and brightly stained with chromomycin A3 after restriction enzyme digestion, are localized on the border with euchromatin in the majority of chromosomes of Equus caballus and E. przewalskii. In contrast to chromosome 5 of E. caballus, acrocentric chromosomes of E. prezewalskii which are homologous to this chromos...
Pavlinov IIa, Nanova OG, Spasskaia NN.Interrelations between some forms of group variation (FGVs) (age, sex, geographic, inter-species, differences among breeds) of 12 to 15 measurable skull traits are studied in 6 mammal species (pine marten, polar fox, Przewalskii horse, and 3 jird species) by means of dispersion analysis (model III, MANOVA). The above FGVs are considered as factors in the MANOVA, and skull traits are considered as dependent variables. To obtaine commeasurables estimates for the FGVs, each of them is assessed numerically as a portion of its dispersion in the entire morphological disparity defined for each charac...
Chopineau M, Stewart F.Reverse transcription-PCR was used to clone the coding region of the donkey (Equus asinus) glycoprotein hormone alpha-subunit transcript from pituitary gland RNA. The donkey alpha-subunit sequence demonstrated considerable identity with the horse (97% at the nucleotide level), confirming the very close evolutionary linkage between these two species. The predicted amino acid sequence revealed that the donkey alpha-subunit has the same unusual C-terminus as the horse alpha-subunit, when compared with all other mammalian alpha-subunits, including a Tyr-His transposition between positions 87 and 9...
Melrose PA, Knigge KM.The present study describes and compares the topography of alpha-melanocyte-stimulating hormone (alpha-MSH)-immunoreactive neurons in the forebrain of rats and horses. Two groups of immunoreactive cells were present in both species. These groups were distinguished by their cross-immunoreactivity and topography. The topography of cell bodies with cross-immunoreactivity for peptides derived from pro-opiomelanocortin (POMC) including adrenocorticotropin, 16K, alpha-MSH and beta-endorphin was similar in both species. However, the topography of perikarya which stained only for alpha-MSH, and not fo...
Ben-Menahem D, Grotjan HE.Chorionic gonadotropins (CG) are unique because they have a carboxyl terminal peptide (CTP) extension on their beta subunits that prolongs circulatory survival. CGbeta genes from the human being and horse have evolved from ancestral luteinizing hormone (LH) beta genes by different pathways that involve deletions that change the reading frames and yield a CTP. Here we further review our previous analysis, aimed at determining whether LHbeta genes in non-primate, non-equid species inherently possess DNA sequences that encode CTP-like domains. In multiple mammalian species, simple frame-shift mut...
Kniazev SP, Reissmann M, Wagner HJ, Kuraĭ MV, Samovolov NV.Results of the first in Russia survey of the gene pool of the breeding nucleus of the Russian population of thoroughbred horses by means of PCR analysis of the E (Extension) locus MC1R gene mutations are presented. The data on the structure of breeding populations from the leading stud farms Voskhod and Oros with regard to color phenotypes as well as genotype and allele frequencies are presented. The population structure parameters are discussed with respect to possible specific features of microevolution processes.
Williams RC.The evolutionary distance between two sets of proteins was estimated using the techniques of Miyata and Yasunaga (1980) and Kimura (1980). Human beta 2-microglobulin was compared with the homologous murine molecule, while human and equine alpha-globin were similarly treated. It was found that a large amount of molecular evolution has occurred in beta 2-microglobulin since its divergence from the common ancestor of mice and humans. Kimura's estimate of evolutionary distance, K, is 0.353, while those of Miyata and Yasunaga are KS = 0.708 and KA = 0.171. The respective values for human and equine...
