Establishment and maintenance of colonies of parthenogenetic whiptail lizards

Townsend, Carol R.

doi:10.1111/j.1748-1090.1979.tb00533.x

Cited by 24 publications

(14 citation statements)

References 10 publications

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“…Laboratory colonies of A. exsanguis, A. inornata, A. tesselata, and A. exsanguis x A. inornata hybrids were established from animals collected in Socorro, Sierra, and Otero Counties, NM, under a permit from the New Mexico Department of Game and Fish (permit numbers 3199 and 3395). Animals were propagated and maintained in the Reptile and Aquatics Facility under conditions similar to a previously published description of captive lizard husbandry (43) and in compliance with protocols approved by the Institutional Animal Care and Use Committee of the Stowers Institute for Medical Research.…”

Section: Methodsmentioning

confidence: 99%

Laboratory synthesis of an independently reproducing vertebrate species

Lutes

Baumann

Neaves

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Speciation in animals commonly involves an extrinsic barrier to genetic exchange followed by the accumulation of sufficient genetic variation to impede subsequent productive interbreeding. All-female species of whiptail lizards, which originated by interspecific hybridization between sexual progenitors, are an exception to this rule. Here, the arising species instantaneously acquires a novel genotype combining distinctive alleles from two different species, and reproduction by parthenogenesis constitutes an effective intrinsic barrier to genetic exchange. Fertilization of diploid parthenogenetic females by males of sexual species has produced several triploid species, but these instantaneous speciation events have neither been observed in nature nor have they been reconstituted in the laboratory. Here we report the generation of four self-sustaining clonal lineages of a tetraploid species resulting from fertilization of triploid oocytes from a parthenogenetic Aspidoscelis exsanguis with haploid sperm from Aspidoscelis inornata. Molecular and cytological analysis confirmed the genetic identity of the hybrids and revealed that the females retain the capability of parthenogenetic reproduction characteristic of their triploid mothers. The tetraploid females have established self-perpetuating clonal lineages which are now in the third generation. Our results confirm the hypothesis that secondary hybridization events can lead to asexual lineages of increased ploidy when favorable combinations of parental genomes are assembled. We anticipate that these animals will be a critical tool in understanding the mechanisms underlying the origin and subsequent evolution of asexual amniotes.hybrid speciation | polyploidy | Cnemidophorus | unisexual

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Section: Methodsmentioning

confidence: 99%

Laboratory synthesis of an independently reproducing vertebrate species

Lutes

Baumann

Neaves

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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“…Lizards in laboratory colonies were maintained at the AMNH as described by Townsend (1979) and Townsend and Cole (1985). Following oviposition, eggs were removed from the cage and allowed to develop at room temperature.…”

Section: Laboratory Maintenance Of Reproducing Lizardsmentioning

confidence: 99%

Morphological Variation in a Unisexual Whiptail Lizard (Aspidoscelis exsanguis) and One of Its Bisexual Parental Species (Aspidoscelis inornata) (Reptilia: Squamata: Teiidae): Is the Clonal Species Less Variable?

Cole

Taylor

Townsend

2016

American Museum Novitates

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Two clonal lineages, each comprising multiple generations of unisexual A. exsanguis, were produced in the laboratory from two lizards that were collected at the same locality in the field. Based on 10 meristic and four additional characters, we assessed morphological scores and relative variation as follows: (1) between the two laboratory lineages; (2) between these lineages pooled and samples of A. exsanguis and the bisexual (gonochoristic) A. inornata from the field; and (3) between field samples of the clonal lizards and A. inornata from a nearby locality. The two lineages differed significantly in the means and variances of two univariate characters and the two most informative multivariate characters. Contrary to expectations, the pooled sample of cloned laboratory lineages of A. exsanguis were as variable as the bisexual species in all 10 univariate characters and four important multivariate characters.

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“…Lizards were caught in the field, held temporarily at the Southwestern Research Station (SWRS, Portal, Arizona), then flown to New York and maintained in a laboratory colony at the American Museum of Natural History by our usual methods (Cole and Townsend, 1977;Townsend, 1979;Townsend and Cole, 1985). Note, however, that there are problems yet to be resolved in order to maximize success with captive whiptail lizards (Porter et al, 1994).…”

Section: Laboratory Maintenance Of Lizardsmentioning

confidence: 99%

“…In some cases there were significant differences in body size, which may have affected physical aspects of mating compatibility. Less conspicuous was the fact that the health for some individuals varied during captivity, and this affected their behavior and viability of their eggs, as some contracted an infection for a while (e.g., respiratory; Townsend, 1979), some developed metabolic bone disease (e.g., Townsend and Cole, 1985), and others had complications from unknown factors that affected reproduction (e.g., Porter et al, 1994). Consequently, in the laboratory, failure of a clutch of eggs to hatch was not necessarily because they contained hybrid embryos.…”

Section: Effort Expended To Obtain the Hybridsmentioning

confidence: 99%

Laboratory Hybridization Among North American Whiptail Lizards, IncludingAspidoscelis Inornata Arizonae × A. tigris marmorata(Squamata: Teiidae), Ancestors of Unisexual Clones in Nature

Cole¹,

Hardy

Dessauer

et al. 2010

American Museum Novitates

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The natural origin of diploid parthenogenesis in whiptail lizards has been through interspecific hybridization. Genomes of the parthenogens indicate that they originated in one generation, as the lizards clone the F 1 hybrid state. In addition, hybridization between diploid parthenogens and males of bisexual species has resulted in triploid parthenogenetic clones in nature. Consequently, the genus Aspidoscelis contains numerous gonochoristic (= bisexual) species and numerous unisexual species whose closest relatives are bisexual, and from whom they originated through instantaneous sympatric speciation and an abrupt and dramatic switch in reproductive biology. In order to study this phenomenon more closely, with hopes (unfulfilled) to witness the origin of parthenogenetic cloning in one generation, we maintained whiptail lizards in captivity. For more than 29 years, we caged males of bisexual species with females of bisexual and of unisexual species in attempts to obtain laboratory hybrids. Hybrids were raised to adulthood to see whether they would reproduce, but none did. The hybrid status of suspected laboratory hybrids was confirmed by karyotypic, allozyme, and morphological analyses, and histological studies were made on reproductive tissues of the hybrids, which were apparently sterile.The present paper focuses on the laboratory hybrids of two bisexual species, A. inornata arizonae (♀) × A. tigris marmorata (♂). These three individuals from one clutch of eggs were the only hybrids between two bisexual species that we obtained. The hybrids had a karyotype, allozymes (21 loci tested), and external morphology that were similar to those of A. neomexicana, which is a diploid parthenogen that had a hybrid origin in nature that was the reciprocal cross: A. t. marmorata (♀) × A. inornata (♂). Histological study showed that the largest and oldest laboratory hybrid raised, which appeared to be a female with inherited X chromosome of A. t. marmorata, was an intersex with an enormous adrenal. The other hybrid that reached adult size, a male, was also apparently sterile.Later, we review and summarize the information on the other laboratory hybrids we obtained over the years. These include two different combinations of hybrids between a male of a bisexual species and females of unisexual species (one diploid, one triploid), producing triploid and tetraploid hybrids, respectively, as a haploid genome from the male was added to the cloned egg. Considering only those specimens whose hybrid status was confirmed with genetic analyses, a total of only five hybrids from three crosses were obtained over 29 years. The effort involved having a total of 74 males of four species caged with 156 females of nine species, where individuals were caged together for at least six months (or less, if mating behavior was observed).Despite our extensive efforts to provide for their comfort and best health and captive environment, the lizards at times experienced health problems such as metabolic bone disease and a Salmonella infection. ...

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Establishment and maintenance of colonies of parthenogenetic whiptail lizards

Cited by 24 publications

References 10 publications

Laboratory synthesis of an independently reproducing vertebrate species

Laboratory synthesis of an independently reproducing vertebrate species

Morphological Variation in a Unisexual Whiptail Lizard (Aspidoscelis exsanguis) and One of Its Bisexual Parental Species (Aspidoscelis inornata) (Reptilia: Squamata: Teiidae): Is the Clonal Species Less Variable?

Laboratory Hybridization Among North American Whiptail Lizards, IncludingAspidoscelis Inornata Arizonae × A. tigris marmorata(Squamata: Teiidae), Ancestors of Unisexual Clones in Nature

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