Survey of zona pellucida antigens for immunocontraception of cats

The purpose of this study was to screen a panel of native zona pellucida (ZP) antigens isolated from five mammalian species for immunocontraceptive activity in the cat (Felis catus). Native soluble-isolated ZP (SIZP) was prepared from the ovaries of cows (bZP), cats (fZP), ferrets (feZP), dogs (cZP), and mink (mZP). Vaccines were constructed using SIZP from each of the above species encapsulated in liposomes suspended in saline and emulsified with Freund's complete adjuvant (SpayVac). Female cats were immunized once (n = 3 cats per group). Serum was collected for determination of antibody titers against SIZP and for binding of antibodies to feline ovaries. All cats responded to immunization by producing anti-SIZP antibodies. The most immunogenic SIZP in cats was from mink, followed by feZP, cZP, and fZP in descending order. Antibodies had low reactivity for fZP, and no reactivity against feline ovaries was detected by immunohistochemistry. A breeding trial was commenced 20 weeks after immunization. All cats became pregnant, averaging 4.1 +/- 0.7 viable kittens per litter. We have previously shown that porcine SIZP is not an effective antigen for immunocontraception of cats. In this study, SIZP from five other mammalian species were immunogenic in the cat, but ZP antibodies failed to bind to fZP in situ, and fertility was not impeded.     

Reproductive fertility of cloned male cats derived from adult somatic cell nuclear transfer

This study was designed to investigate the reproductive fertility by the natural breeding of cloned male cats with domestic female cats, and to measure endocrine hormone concentration related to male reproduction such as testosterone, leutinizing hormone (LH), and follicle stimulating hormone (FSH). Cloned A, B, C, and D cats produced three, two, four, and five kittens after natural mating with four domestic female cats, respectively, despite later puberty of the cloned D cat than those of the other cloned male cats. Three of the 14 kittens expressed an odd eye color, which was produced by 1 and 2 from cloned A and B cats. The eye color of the other F1 kittens varied from nine brown to two blue. Body weight at birth ranged from 72.9 to 134.0 g. Although clone D had a poorer libido and entered puberty later than those of the other cloned male cats, he produced gonadal hormones within the average range. Four of the cloned male cats had normal fertility. The concentration of gonadal hormones in cloned male cats was similar to two control and donor cats. The concentration of testosterone was not significantly different among clones A, B, C, D, and control cats (5.99 +/- 5.68; 3.46 +/- 2.81; 6.41 +/- 2.17; 3.75 +/- 0.34; 4.0 +/- 3.63 ng/mL, p < 0.05). The concentrations of LH and FSH were not significantly different among the cloned cats (p < 0.05). Seven male and seven female (in total 14) kittens were produced by the natural breeding with four domestic female cats. These results indicated that cloned male cats have normal reproductive fertility and lie within the normal range of gonadal hormone production. All F1 kittens were produced by natural breeding and delivery, and are still alive and have normal growth health (27 months age).     

Embryo technology in conservation efforts for endangered felids

Most of the 36 species of wild cats are classified as threatened, vulnerable or endangered due to poaching and habitat loss. The important role of assisted reproduction techniques (ART) as part of a multifaceted captive breeding program for selected wild cat species is gradually gaining acceptance. This recognition is a result of the progress made during the last decade in which the feasibility of oocyte recovery from gonadotropin-treated females, in vitro fertilization, embryo cryopreservation and embryo transfer (ET) was demonstrated in the domestic cat (Felis catus). Additionally, embryos have been produced in vitro from oocytes matured in vitro after recovery from ex situ ovaries of both domestic and non-domestic cat species and domestic kittens have been born following transfer of these embryos. In vitro fertilization has been successful in at least one-third of wild cat species and kittens were born after transfer of Indian desert cat (Felis sylvestris ornata) embryos into a domestic cat and con-specific transfer of tiger (Panthera tigris) embryos. The domestic cat is not only a valuable model for development of in vitro techniques but may serve as a recipient of embryos from several species of small wild cats.     

Immunolocalization of zona pellucida antigens in the ovarian follicle of dogs, cats, horses and elephants

A comparative evaluation of the location of immunoreactive porcine zona pellucida (pZP) glycoproteins was performed with polyclonal rabbit anti-pZP antibodies on ovarian sections of the dog, cat, horse, and elephant. For this, formalin (light microscopy) and glutaraldehyde (transmission electron microscopy [TEM]) fixed ovarian sections were incubated with antibodies raised against highly purified pZP. Staining patterns were determined with diaminobenzidine (DAB) at the light level. The dog ZP had a distinct staining distribution that is characterized by intense staining around the periphery of the ZP and the oolemma and less dense staining throughout the width of the ZP. In dog follicles that contained multiple oocytes, there were oocytes of identical and dissimilar stages. Cat ovarian sections showed uniform staining of the ZP. Horse results showed uniform staining of ZP and ooplasm, and granulosa cells (GC). Elephant sections showed staining of the ZP with dense staining at the oolemma, as well as staining of the ooplasm. In all species the staining of the ZP was not evident until GC differentiation. In all cases there was no staining of ovarian tissue with control normal rabbit serum. Specific staining patterns of ZP were evaluated by TEM and immunogold staining. The immunogold-linked anti-pZP antibodies stained the ZP matrix in all species. There was staining of ooplasm organelles suggesting that ZP secretion originates from the oocyte of the dog and cat. In addition, follicular and ZP measurements were taken that allowed accurate characterization of follicle stage. These findings suggest that in all four species the ZP is recognized by anti-pZP antibodies and there is also evidence to suggest the possible origins of ZP glycoproteins.     

DNA methylation status in somatic and placenta cells of cloned cats

We recently produced 11 cloned kittens by somatic cell nuclear transfer (SCNT) using fibroblasts from a feline fetus (donor A, three kittens), an adult domestic cat (donor B, one kitten), and a deaf adult Turkish Angora cat (donor C, seven kittens). Two kittens were stillborn and three died a month after birth. The donor C-derived kittens did not share their donor's eye color or deafness. To test whether this and the low cloning success rate are due to epigenetic modifications, we compared the methylation of somatic and placental cells from the cloned cats and domestic normal cats by bisulfite mutagenesis sequencing analysis. The DNA methylation of somatic cells from the cloned kittens ranged from 78.0% to 88.9%, and did not differ significantly depending on whether they were stillborn, died early after birth, or were healthy. Donors B and C showed similar levels of methylation (77.0% and 79.1%, respectively), as did somatic cells from normal domestic and Turkish Angora cats (range, 75.7-88.0%). However, donor A showed less methylation (70.6%) than the somatic cells from the kittens derived from it (range, 82.2-88.9%). Moreover, placental cells from three donor C-derived kittens showed significantly higher DNA methylation (range, 76.7-80.5%) than placental cells from normal domestic cats (range, 64.2-74.9%). Thus, methylation of satellite regions in somatic cells may not be responsible for the stillbirth, early death, or different eye and hearing attributes of cloned cats. However, hypermethylation in the placenta of cloned cats may be responsible for low success rates in cloning cats.     

Contraceptive potential of porcine zona pellucida in cats

The contraceptive potential of solubilized porcine zona pellucida (spZP) was studied in 2 groups of cats after active immunization using slightly different protocols. Cats from Group 1 (n = 3) were immunized with a total of 300 8g spZP divided in 4 s.c. multisite injections (each of 37.5 8g) given at 10 day intervals followed by a booster 150 days after the initial immunization. Cats from Group 2 (n = 5) were immunized with a total of 400 8g spZP divided in 4 i.m. injections (each of 50 8g) given at 2 wk intervals followed by a booster 92 days after initial immunization. Immunogen was emulsified in Complete Freund Adjuvant for the first dose and in Incomplete Freund Adjuvant for the following 3 doses. The respective controls were immunized in the same manner using only adjuvant and PBS. Immunofluorescence studies showed intense fluorescence on the zona pellucida (ZP) of the oocytes isolated from immunized cats, as well as on the ZP of porcine and cat oocytes preincubated in immune sera. Sera from cats immunized with spZP inhibited in vitro binding was demonstrated in oocytes isolated from immunized group 1 cats. In vivo fertility data in Group 2 cats revealed that only 1 of 5 cats became pregnant, the one with the lowest anti-spZP titer. The results from the experiments reported above, suggest that in this preliminary study spZP can elicit antibodies with contraceptive potential in actively immunized female cats.     

Lynx reproduction – Long-lasting life cycle of corpora lutea in a feline species

A review of lynxes’ reproductive biology and comparison between the reproductive cycles of the domestic cat and lynxes is presented. Three of the four lynx species (the bobcat excluded) express quite similar reproductive pattern (age at sexual maturity, estrus and pregnancy length, litter size). Similarly to the domestic cat, the bobcat is polyestric and can have more than one litter per year. Domestic cats and many other felid species are known to express anovulatory, pregnant and pseudo-pregnant reproductive cycles in dependence on ovulation induction and fertilization. The formation of corpora lutea (CLs) occurs after ovulation. In pregnant animals, luteal function ends with parturition, whereas during pseudo-pregnancy a shorter life span and lower hormone secretion are observed. The life cycle of corpora lutea in Eurasian lynxes is different from the pattern described in domestic cats. Lynx CLs produce progestagens in distinctive amounts permanently for at least two years, regardless of their origin (pregnancy or pseudo-pregnancy). It is suggested that long-lasting CLs induce a negative feedback to inactivate folliculogenesis, turning a normally polyestric cycle observed in most felids into a monoestric cycle in lynxes.     

Monoclonal antibodies to rabbit and pig zonae pellucidae distinguish species-specific and shared antigenic determinants

Monoclonal antibodies against rabbit or porcine zonae pellucidae (ZP) demonstrate species-specific and shared antigenic determinants. In addition, these antibodies are used to characterize the biochemical nature of these determinants. All of six monoclonal antibodies developed against porcine ZP react with porcine but not with rabbit ZP. Only one of seven monoclonal antibodies developed against rabbit ZP cross-reacts with porcine ZP. None of these antibodies recognized antigens associated with other tissues tested. High-resolution, two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) followed by immunoblotting was used to demonstrate that the cross-reactive antibody recognizes an antigenic determinant which is associated with the major low molecular weight glycoprotein of both the pig and rabbit ZP. Since this antibody recognizes all charge species of this glycoprotein, it is apparent that the antigenic determinant recognized by this antibody involves protein. Further studies demonstrate that proteolytic digestion of ZP will destroy the antigenic determinant while glycosidic digestion of ZP has no effect on antibody binding. Although polyclonal antibodies to this glycoprotein inhibit sperm from binding to the zona pellucida, this monoclonal antibody does not affect sperm binding. None of the species-specific antibodies recognize ZP glycoproteins following 2D-PAGE. This is a property typical of antibodies directed against conformational antigenic determinants. The presence of common as well as unique zona antigenic determinants could explain why ZP proteins induce heteroantibodies which result in infertility while alloimmunization has no effect on fertility.     

Nuclear transfer in cats and its application

Nuclear transfer (NT) technology is typically used for generating identical individuals, but it is also a powerful resource for understanding the cellular and molecular aspects of nuclear reprogramming. Most recently, the procedure has been used in humans for producing patient-specific embryonic stem cells. The successful application of NT in cats was demonstrated by the birth of domestic and non-domestic cloned kittens at a similar level of efficiency to that reported for other mammalian species. In cats, it has been demonstrated that either in vivo or in vitro matured oocytes can be used as donor cytoplasts. The length of in vitro oocyte maturation affects in vitro development of reconstructed embryos, and oocytes matured in vitro for shorter periods of time are the preferred source of donor cytoplasts. For NT, cat somatic cells can be synchronized into the G0/G1 phase of the cell cycle by using different methods of cell synchronization without affecting the frequency of in vitro development of cloned embryos. Also, embryo development to the blastocyst stage in vitro is not influenced by cell type, but the effect of cell type on the percentage of normal offspring produced requires evaluation. Inter-species NT has potential application for preserving endangered felids, as live offspring of male and female African wildcats (AWC, Felis silvestris lybica) have been born and pregnancies have been produced after transferring black-footed cat (Felis nigripes) cloned embryos into domestic cat (Felis silvestris catus) recipients. Also, successful in vitro embryo development to the blastocyst stage has been achieved after inter-generic NT of somatic cells of non-domestic felids into domestic cat oocytes, but no viable progeny have been obtained. Thus, while cat cytoplasm induces early nuclear remodeling of cell nuclei from a different genus, the high incidence of early embryo developmental arrest may be caused by abnormal nuclear reprogramming. Fetal resorption and abortions were frequently observed at various stages of pregnancy after transfer of AWC cloned embryos into domestic cat recipients. Abnormalities, such as abdominal organ exteriorization and respiratory failure and septicemia were the main causes of death in neonatal cloned kittens. Nonetheless, several live domestic and AWC cloned kittens have been born that are seemingly normal and healthy. It is important to continue evaluating these animals throughout their lives and to examine their capability for natural reproduction.     

Communal nursing in the domestic cat,Felis catus

Communal nursing in the domestic cat has been observed in group living conditions. (In high density conditions, cats have social lives.) In our laboratory, when females were kept in the same cage, they delivered kittens nearly simultaneously, and started to nurse their kittens communally. This process, which was videotaped, was shown to be begun by the mother’s retrieving kittens. They seemed to have no ability to discriminate their own kittens from those of others, as our test of recognition of kittens showed. Communal nursing resulted in high mortality of kittens, the release of mothers from caring for kittens, and incomplete reproductive division of labour. Abortion was often observed in group-living cats in captivity. High mortality and low birthrate are helpful in controlling population. All members of the group were very familiar to each other, so that they formed a ‘pseudo’-kin group.     

Antigenic comparison of five species of mammalian zonae pellucidae

A comparison of glycoproteins of the zona pellucida (ZP) of five different mammalian species (cat, dog, rabbit, pig, and rat) has been made using polyclonal and monoclonal antibodies. In an enzyme-linked immunosorbent assay (ELISA), polyclonal antisera against total rabbit and pig ZP recognize their homologous ZP to the greatest extent but also detect crossreactive antigenic determinants in the ZP of all other species tested. Polyclonal antibodies against each of two purified rabbit ZP glycoproteins or one purified pig ZP glycoprotein also show some recognition of heterologous (pig, cat, and dog) ZP, but not rat ZP. Monoclonal antibodies (McR5-rabbit ZP protein determinant; McPSI-determinant associated with post-translational modifications of pig ZP proteins such as carbohydrates) further demonstrate that specific determinants are shared between some but not all of these mammalian species. For example, both of these antibodies recognize distinct determinants which are most abundant in pig and cat ZP. However, McR5 recognizes a determinant on all species of ZP except the rat, while McPSI does not recognize either the rabbit or rat ZP. Collectively, these studies suggest that the molecules of the pig, dog, and cat ZP are more closely related to each other than to those of the rabbit ZP, while there is little similarity with rat ZP molecules. Immunoblot analysis of ZP glycoproteins separated by two-dimensional polyacrylamide gel electrophoresis was used to identify antigenic relationships among four different species. The polyclonal antisera show that all of the major proteins of pig, rabbit, cat, and dog ZP are antigenically related.(ABSTRACT TRUNCATED AT 250 WORDS)     

Genetic and phylogenetic divergence of feline immunodeficiency virus in the puma (Puma concolor).

Feline immunodeficiency virus (FIV) is a lentivirus which causes an AIDS-like disease in domestic cats (Felis catus). A number of other felid species, including the puma (Puma concolor), carry a virus closely related to domestic cat FIV. Serological testing revealed the presence of antibodies to FIV in 22% of 434 samples from throughout the geographic range of the puma. FIV-Pco pol gene sequences isolated from pumas revealed extensive sequence diversity, greater than has been documented in the domestic cat. The puma sequences formed two highly divergent groups, analogous to the clades which have been defined for domestic cat and lion (Panthera leo) FIV. The puma clade A was made up of samples from Florida and California, whereas clade B consisted of samples from other parts of North America, Central America, and Brazil. The difference between these two groups was as great as that reported among three lion FIV clades. Within puma clades, sequence variation is large, comparable to between-clade differences seen for domestic cat clades, allowing recognition of 15 phylogenetic lineages (subclades) among puma FIV-Pco. Large sequence divergence among isolates, nearly complete species monophyly, and widespread geographic distribution suggest that FIV-Pco has evolved within the puma species for a long period. The sequence data provided evidence for vertical transmission of FIV-Pco from mothers to their kittens, for coinfection of individuals by two different viral strains, and for cross-species transmission of FIV from a domestic cat to a puma. These factors may all be important for understanding the epidemiology and natural history of FIV in the puma.     

Production of second-generation cloned cats by somatic cell nuclear transfer

We successfully produced second-generation cloned cats by somatic cell nuclear transfer (SCNT) using skin cells from a cloned cat. Skin cells from an odd-eyed, all-white male cat (G0 donor cat) were used to generate a cloned cat (G1 cloned cat). At 6 months of age, skin cells from the G1 cloned cat were used for SCNT to produce second-generation cloned cats. We compared the in vitro and in vivo development of SCNT embryos that were derived from the G0 donor and G1 cloned donor cat's skin fibroblasts. The nuclei from the G0 donor and G1 cloned donor cat's skin fibroblasts fused with enucleated oocytes with equal rates of fusion (60.7% vs. 58.8%, respectively) and cleavage (66.3% vs. 63.4%). The 2-4-cell SCNT embryos were then transferred into recipients. One of the five recipients of G0 donor derived NT embryos (20%) delivered one live male cloned kitten, whereas 4 of 15 recipients of the G1 cloned donor cat derived NT embryos (26%) delivered a total of seven male second-generation cloned kittens (four live kittens from one surrogate, plus two stillborn kittens, and one live kitten that died 2d after birth from three other surrogate mothers). The four second-generation cloned kittens from the same surrogate all had a white coat color; three of the four second-generation cloned kittens had two blue eyes, and one of the second-generation cloned kittens had an odd-eye color. Despite low cloning efficiency, cloned cats can be used as donor cats to produce second-generation cloned cats.     

Comparative evaluation of seminal,vaginal, and rectal bacterial flora in the cheetah and domestic cat

To determine the status and potential impact of microorganisms on reproductive health, bacterial cultures were evaluated from cheetah seminal, vaginal, and rectal swabs and the results compared to those from clinically healthy, domestic cats. Aerobic bacteria were isolated in the semen from 26 of the 40 (65.0%) cheetahs and 25 of the 27 (92.6%) domestic cats. Gram-negative organisms predominated in the electroejaculates of both species, accounting for >70% of the total bacterial isolates. The most common seminal organism in both species was hemolytic Escherichia coli. Bacteria were isolated from vaginal samples obtained from 49 of the 67 (73.1%) cheetahs and 46 of the 49 (93.9%) domestic cats. Gram-negative organisms dominated, representing >63% of the vaginal bacteria, and again hemolytic E. coli was the most prevalent isolate in both species. None of the cheetah or domestic cat vaginal cultures contained Mycoplasma spp. or Ureaplasma spp. Numerous gram-negative and gram-positive bacteria were identified in rectal cultures of 73 cheetahs and 60 domestic cats, but hemolytic E. coli clearly was the most common isolate. Within each species, a comparison between electroejaculates that were positive vs. negative for hemolytic E. coli growth revealed no differences in sperm concentration, sperm motility ratings, or the proportion of structurally abnormal spermatozoa. Neutrophils were not detected in any of the 67 felid ejaculates, and the presence of seminal hemolytic E. coli was unrelated to fertility, on the basis of past ability to sire young or fertilize oocytes in vitro. Vaginal cytologic evaluations in both the cheetah and domestic cat indicated that hemolytic E. coli was not associated with a pathologic inflammatory response. Overall fecundity and proven ability to produce young were similar between females producing positive or negative vaginal cultures for E. coli. These findings indicate that commensal bacteria exist in the reproductive tract of the cheetah and domestic cat, and these organisms constitute normal, apparently innocuous bacterial microflora in the semen and vagina. © 1993 Wiley-Liss, Inc.     

Implementation of a feral cat management program on a university campus

In August 1998, Texas A&M University implemented on campus a trap-test-vaccinate-alter-return-monitor (TTVARM) program to manage the feral cat population. TTVARM is an internationally recognized term for trapping and neutering programs aimed at management of feral cat populations. In this article we summarize results of the program for the period August 1998 to July 2000. In surgery laboratories, senior veterinary students examined cats that were humanely trapped once a month and tested them for feline leukemia and feline immunodeficiency virus infections, vaccinated, and surgically neutered them. They euthanized cats testing positive for either infectious disease. Volunteers provided food and observed the cats that were returned to their capture sites on campus and maintained in managed colonies. The program placed kittens and tame cats for adoption; cats totaled 158. Of the majority of 158 captured cats, there were less kittens caught in Year 2 than in Year 1. The proportion of tame cats trapped was significantly greater in Year 2 than in Year 1. The prevalence found for feline leukemia and feline immunodeficiency virus ELISA test positives was 5.8% and 6.5%, respectively. Following surgery, 101 cats returned to campus. The project recaptured, retested, and revaccinated more than one-fourth of the cats due for their annual vaccinations. The program placed 32 kittens, juveniles, and tame adults for adoption. The number of cat complaints received by the university's pest control service decreased from Year 1 to Year 2.     

Genetic diversity in domestic cats Felis catus of the Tsushima Islands, based on mitochondrial DNA cytochrome b and control region nucleotide sequences

Nucleotide sequences of mitochondrial DNA (mtDNA) of 50 domestic cats (Felis catus) obtained from the Tsushima Islands were determined and the genetic diversity was analyzed. In the cats, six haplotypes of the complete cytochrome b sequences (1,140 base-pairs, bp) and ten haplotypes of the partial control region sequences (350 bp) were identified. Haplotypes obtained from both genes showed existence of at least 11 maternal lineages of domestic cats in Tsushima. Mean values of polymorphic site numbers and sequences differences in the control region were 2.4 times and 1.8 times higher than those in the cytochrome b gene, respectively. Our results support the idea that the evolutionary rate of the control region was faster than that of the cytochrome b as reported in other mammals. Molecular phylogenetic trees showed the similar clustering of haplotypes for both genes. Meanwhile, no individual variations within the Tsushima leopard cat (Felis bengalensis euptilura), which is native to Tsushima, were observed, possibly as a result of genetic drift in the small ancestral population by geographical isolation. In contrast, the diversity of the domestic cat population was higher than that of the leopard cats, because the genetic variability of the former's founders, which were repeatedly brought to Tsushima in the past, still remains. In addition, no sequences of the leopard cat mtDNA were detected in any domestic cats. However, because the possibility that the domestic cat would crossbreed with the leopard cat cannot be denied, genetic monitoring of two species is necessary to biological conservation in Tsushima.     

Clinical management of pregnancy in cats

Average gestation length in domestic cats is 65.6 days, with a range of 52-74 days. Average reported litter size is 4.0 kittens per litter; litter size is not correlated with number of matings in a given estrus. Superfecundation is common in domestic cats; superfetation never has been definitively proven to occur. Eclampsia may occur during pregnancy in queens, with non-specific clinical signs. Ectopic pregnancy and uterine torsion have been reported. Pregnancy loss may be due to infectious causes, including bacteria, viruses or protozoa, or non-infectious causes, such as hypoluteoidism and chromosome errors.     

Managing feral cats on a university's campuses: how many are there and is sterilization having an effect?

Worldwide domestic and feral cat (Felis catus) numbers have increased. Concerns regarding high populations of feral cats in urban areas include wildlife predation, public nuisance, and disease. This study aimed to estimate the size of the feral cat population on 5 campuses of the University of KwaZulu-Natal, South Africa, to determine whether sterilization has an effect and to make management recommendations. The study used both the total count and mark-recapture methods to estimate the feral cat population on each campus. The study chose a noninvasive method of taking photographs to "mark" individuals and record those who were sterilized. The study estimated a total of 186 cats on all campuses and density at 161 cats km(-2). There was a negative relationship between sterilization and numbers. Sites with higher sterilization showed a lower proportion of younger cats. At the average sterilization of 55%, the population, according to predictions, would remain stable at fecundity, survival, and immigration rates reported by cat caretakers. However, caretakers underestimated cat abundance by 7 ± 37 SD%. Caretakers' feral cat sterilization and feeding programs appear to provide a service to the university community. Key management recommendations were to increase sterilization to 90% to reduce the population over the long term and to raise funds to support the costs incurred by voluntary cat caretakers.     

The mating system of feral cats (Felis catus L.) in a sub-Antarctic environment

In order to investigate the mating system of domestic cats living in a sub-Antarctic environment, we sampled 40 kittens belonging to 13 litters (from 9 mothers) in the main island of Kerguelen archipelago. We genotyped females and kittens using nine microsatellite markers. Contrary to what has been found in environments under strong human influence where the mating system is polygynous or promiscuous, and where male cats were in general not able to control the access to receptive females, results show that kittens from the same litter were sired by only one male in the Kerguelen population. It is hypothesised that this pattern is the closest to that of the original environment of adaptation.