Temperature-induced meristic variation among three homozygous genotypes (clones) of the self-fertilizing fish Rivulus marmoratus

Embryos of clones DS, NA, and M were reared at sustained temperatures of 19, 25, and 31 °C. Diverse evidence indicates a closer genetic affinity between DS and NA than between either and M. DS and NA converged and M diverged regarding thermal responses of vertebrae, and anal and pelvic rays; DS and M converged and NA diverged regarding responses of pectoral, caudal, and dorsal rays. For vertebrae and pectoral rays, response curves were declivous; for caudal rays, inverted-V shaped; for anal rays, upright-V shaped (NA), inverted-V shaped (DS), declivous (M); for dorsal rays, declivous (NA), upright-V shaped (DS and M); for pelvic rays, subhorizontal (DS and NA), inverted-V shaped (M). The vertebral response curves of DS and NA diverged at 25 °C, converging at 19 and 31 °C. Caudal counts increased between 31 and 25 °C, caudal and precaudal, between 25 and 19 °C. Vertebral differences (as percentage of the midpoint count) exceeded any of previous experiments on species other than R. marmoratus. At 19 and 31 °C pelvic fins are often lacking, but never in outbreeding R. cylindraceus. Response curves except vertebral ones differed qualitatively between these species. Many kinds of variations, and proportions of phenotypic differences due to genotypic and environmental differences and their interactions are compared.

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Influence of reproductive history of parents on meristic variation in offspring in the cyprinodont fish Rivulus marmoratus

Canadian Journal of Zoology ◽

10.1139/z86-217 ◽

1986 ◽

Vol 64 (7) ◽

pp. 1456-1459 ◽

Cited By ~ 6

Author(s):

D. P. Swain ◽

C. C. Lindsey

Keyword(s):

Reproductive History ◽

The Self ◽

Caudal Fin ◽

Rivulus Marmoratus ◽

Fin Rays ◽

History Of ◽

Meristic Variation

Parent fish from one clone of the self-fertilizing cyprinodont fish Rivulus marmoratus were held under constant conditions, and their offspring were examined for meristic variation associated with their position in the oviposition sequence of parents. In all meristic series counted (vertebrae, and anal, dorsal, pectoral, and caudal fin rays) those offspring produced soon after their parents had begun to lay eggs tended to have fewer parts than did those produced longer after the onset of oviposition. Most meristic differences were due to the low counts produced in embryos laid within 8 days of first oviposition; counts differed little among embryos laid at averages of 22, 86, and 158 days after first oviposition. Differences were most significant for dorsal and anal rays and not significant for caudal rays.

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Extreme vertebral variation induced by temperature in a homozygous clone of the self-fertilizing cyprinodontid fish Rivulus marmoratus

Canadian Journal of Zoology ◽

10.1139/z72-100 ◽

1972 ◽

Vol 50 (6) ◽

pp. 733-744 ◽

Cited By ~ 23

Author(s):

C. C. Lindsey ◽

Robert W. Harrington Jr.

Keyword(s):

Early Development ◽

Gene Pool ◽

The Self ◽

Selective Mortality ◽

Genetic Uniformity ◽

Rivulus Marmoratus ◽

Meristic Variation ◽

Retinal Pigmentation ◽

High Degree ◽

Hatching Temperature

Embryos from one clone of Rivulus marmoratus were reared at various constant temperatures ranging from 19.5 to 31.2C, sustained throughout early development, or else were transferred from 26 to 20C after various periods of development. Resultant vertebral counts were progressively lower at higher sustained temperatures (ranging from 34.94 to 32.57). Vertebral differences expressed as a percentage of the total count were greater in this (7.0%) than in previously reported comparable experiments on 14 other fish species (4.1% or less). In most previous experiments meristic variation may have been due, at least in part, to selective mortality acting on a varied gene pool. In R. marmoratus the high degree of genetic uniformity eliminates the likelihood of selective mortality as a cause of vertebral variation, which must therefore have been environmentally induced. Pectoral ray counts also were lower at higher sustained temperatures; other meristic series did not show sharp responses. Temperature transfer experiments showed that vertebral counts are determined within 4 days at 26C (by first appearance of retinal pigmentation). Pectoral ray counts are not fully determined until about 8 days, shortly before hatching. Temperature breaks produced "shock effect" in pectoral rays but not in vertebrae. The bearing of homozygosity on amplitude of temperature-induced vertebral variation is discussed.

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Meristic variation in a clone of the cyprinodont fish Rivulus marmoratus related to temperature history of the parents and of the embryos

Canadian Journal of Zoology ◽

10.1139/z86-216 ◽

1986 ◽

Vol 64 (7) ◽

pp. 1444-1455 ◽

Cited By ~ 18

Author(s):

D. P. Swain ◽

C. C. Lindsey

Keyword(s):

Fresh Water ◽

Developmental Stages ◽

The Self ◽

Temperature History ◽

Vertebral Number ◽

Rivulus Marmoratus ◽

Temperature Regimes ◽

Meristic Counts ◽

History Of ◽

Meristic Variation

Parents from one clone of the self-fertilizing cyprinodont fish Rivulus marmoratus were held at 25 or 30 °C, and their offspring were subjected to either a sustained temperature of 25 or 30 °C or to a temperature break (abrupt transfer in either direction between 25 and 30 °C) at various developmental stages. Effects of parental temperature before fertilization on meristic counts of offspring were determined both by comparing offspring produced either soon or long after parents had been transferred to a new temperature, and also by examining meristic responses of developing embryos to temperature breaks. Both line of evidence indicate that a parental temperature of 30 °C produces fewer vertebrae (0.31), pectoral rays (0.54), and caudal rays (1.11) than does one of 25 °C, in offspring reared under comparable temperature regimes. Neither line provides clear evidence of an effect of parental temperature on number of anal or dorsal rays in offspring. Responses of all five meristic series to temperature breaks in either direction were extralimitary (beyond the counts produced by sustained incubation at either temperature) and were satisfactorily fitted by an "atroposic" model described previously. Embryos transferred to fresh water during development tended to have higher meristic counts than those with sustained rearing in brackish water, but counts among embryos transferred to fresh water at different developmental stages differed significantly only for caudal rays. Only dorsal ray numbers differed significantly among embryos retained within parents for different times after fertilization. Previous studies claiming uniquely high thermolability of vertebral number in R. marmoratus are re-evaluated; thermolability of vertebral number in R. marmoratus is concluded to be within the range reported for other species.

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The Homozygosity of Clones of the Self-Fertilizing Hermaphroditic Fish Rivulus marmoratus Poey (Cyprinodontidae, Atheriniformes)

The American Naturalist ◽

10.1086/282547 ◽

1968 ◽

Vol 102 (926) ◽

pp. 337-343 ◽

Cited By ~ 52

Author(s):

Robert W. Harrington, ◽

Klaus D. Kallman

Keyword(s):

The Self ◽

Rivulus Marmoratus

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BIOCHEMICAL COMPARISON OF GENETICALLY-DIFFERENT HOMOZYGOUS CLONES (ISOGENIC, UNIPARENTAL LINES) OF THE SELF-FERTILIZING FISH RIVULUS MARMORATUS POEY

Isozymes ◽

10.1016/b978-0-12-472703-8.50033-0 ◽

1975 ◽

pp. 439-453 ◽

Cited By ~ 4

Author(s):

EDWARD J. MASSARO ◽

JANET C. MASSARO ◽

ROBERT W. HARRINGTON

Keyword(s):

The Self ◽

Rivulus Marmoratus ◽

Biochemical Comparison

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Hepatocarcinogenicity of Diethylnitrosamine to the Self-Fertilizing Hermaphroditic Fish Rivulus marmoratus (Teleostomi: Cyprinodontidae)2

JNCI Journal of the National Cancer Institute ◽

10.1093/jnci/73.4.871 ◽

1984 ◽

Keyword(s):

The Self ◽

Rivulus Marmoratus

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Genetic and growth differences in the outcrossings between two clonal strains of the self-fertilizing mangrove killifish

Canadian Journal of Zoology ◽

10.1139/z08-075 ◽

2008 ◽

Vol 86 (9) ◽

pp. 976-982 ◽

Cited By ~ 12

Author(s):

Yukino Nakamura ◽

Koushirou Suga ◽

Yoshitaka Sakakura ◽

Takashi Sakamoto ◽

Atsushi Hagiwara

Keyword(s):

Artificial Insemination ◽

Genetic Architecture ◽

Life History Traits ◽

Fragment Length Polymorphism ◽

The Self ◽

Aflp Analysis ◽

Rivulus Marmoratus ◽

Kryptolebias Marmoratus ◽

Growth Differences ◽

Mangrove Killifish

The populations of the only known self-fertilizing vertebrate Kryptolebias marmoratus (Poey, 1880) (formerly known as Rivulus marmoratus Poey, 1880; Cyprinodontiformes: Aplocheilidae) usually consist of different homozygous lineages; however, heterozygous individuals are found occasionally and ratios of homozygosity and heterozygosity in populations are dependent on the proportion of males. However, it is still unclear what impact male-mediated genetic diversity has on the phenotype of K. marmoratus. To clarify this, we attempted outcrossing between male and hermaphrodite of two different clonal strains with different life-history traits using artificial insemination, and examined the genotypes and growth of the hybrid F2 generation. We detected genetic differences between the two clonal strains using amplified fragment length polymorphism (AFLP) analysis with 3 primer combinations, and then obtained 11 AFLP markers. From a total of 31 artificial inseminations with two clonal strains, 1 of 13 hatched fish clearly indicated heterozygosity. The hybrid F2 generations were also heterozygous. Moreover, the growths of the hybrid F2 generation were intermediate of the parental strains from days 0 to 30. Therefore, outcrossing changes genetic architecture and the new genotypes potentially result in new phenotypes of the subsequent generations of K. marmoratus. It may also play a role in adaptation to new environments and the facilitation of local adaptation.

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