Electrophoretic identification of Ambystoma laterale and Ambystoma texanum as well as their diploid and triploid interspecific hybrids (Amphibia: Caudata) on Pelee Island, Ontario

1985 ◽  
Vol 63 (2) ◽  
pp. 340-347 ◽  
Author(s):  
James P. Bogart ◽  
Lawrence E. Licht ◽  
Michael J. Oldham ◽  
Stephen J. Darbyshire
Keyword(s):  
Interspecific Hybrids ◽  
Gene Dosage ◽  
Electrophoretic Analysis ◽  
Genetic Distances ◽  
Chromosome Counts ◽  
Triploid Female ◽  
Ambystoma Laterale ◽  
Ambystoma Texanum

Ambystoma salamanders from Pelee Island, Ontario, were compared with mainland populations of A. jeffersonianum, A. laterale, and A. texanum using erythrocyte area measurements, chromosome counts, and electrophoretic analysis of proteins coded by 32 loci. The mainland species are characterized by relatively low heterozygosity (H = 0.053–0.11) and high Nei's genetic distances (D = 0.896–1.067). Nine diagnostic loci were found in A. jeffersonianum and five in each of A. laterale and A. texanum. Two loci (SOD-1 and GOT-1) diagnose all three mainland species and provide gene dosage for assessing genome contributions of A. laterale and A. texanum in Pelee Island salamanders. Diploid and triploid female A. texanum × A. laterale hybrids as well as A. laterale and A. texanum occur on Pelee Island.

Breeding behavior and chromosome numbers among New Guinea and Java Impatiens species, cultivated varieties, and their interspecific hybrids

1974 ◽  
Vol 52 (5) ◽  
pp. 923-925 ◽  
Author(s):  
Allan R. Beck ◽  
Jack L. Weigle ◽  
Eric W. Kruger
Keyword(s):  
Chromosome Numbers ◽  
Interspecific Hybrids ◽  
New Guinea ◽  
Chromosome Morphology ◽  
Breeding Behavior ◽  
Chromosome Counts

Impatiens crosses were made among the following: P.I. 349629 (Java), P.I. 349586 (New Guinea), I. Itolstii, and "Tangerine." All crosses were successful except those made with I. Itolstii. Chromosome counts were as follows: P.I. 349629 = 16, P.I. 349586 = 32, I. Itolstii = 16, and "Tangerine" = 8. Chromosome counts of the hybrids were midway between the respective parents. Cytological studies indicated a similarity in chromosome morphology and size among all parents except I. holslii. A new genome count of 4 is reported for the genus Impatiens indicating a ploidy series in which x = 4.

A potential solution to the chromosome instability problem in hexaploid alfalfa, Medicago sativa L.

Genome ◽  
1989 ◽  
Vol 32 (2) ◽  
pp. 302-306 ◽  
Author(s):  
T. J. McCoy
Keyword(s):  
Medicago Sativa ◽  
Interspecific Hybrids ◽  
Chromosome Instability ◽  
Chromosome Stability ◽  
Potential Solution ◽  
Chromosome Counts ◽  
Instability Problem ◽  
Commercial Use ◽  
Medicago Sativa L ◽  
The Cross

Autohexaploid alfalfa (2n = 6x = 48) is chromosomally unstable, which prevents commercial use. The objective of this investigation was to test whether synthesizing Medicago hexaploids (2n = 6x = 48) that are alloautohexaploids results in chromosomally stable hexaploid populations. Previous research in our laboratory demonstrated a lack of affinity between the genomes of alfalfa and M. papillosa Boiss. Triploid (2n = 3x = 24) interspecific hybrids with two M. papillosa genomes and one genome of M. sativa were readily recovered from seed following the cross (2x) M. sativa × (4x) M. papillosa. For this study, the triploids were chromosomally doubled to produce alloautohexaploids, and these alloautohexaploids were used to test chromosome stability in hexaploids with no more than four homologous genomes. Chromosome counts of 47 progeny from intercrossing the alloautohexaploids demonstrated all were hexaploid, indicating chromosome stability. Designing novel genomic combinations based on genomic affinity may result in higher yielding alfalfa populations that have a modified cytogenetic structure.Key words: Medicago cancellata, Medicago papillosa, Medicago saxatilis, genomic affinity, hexaploids.

scholarly journals Populational genetic structure of free-living maned wolves (Chrysocyon brachyurus) determined by proteic markers

2004 ◽  
Vol 64 (3b) ◽  
pp. 639-644 ◽  
Author(s):  
P. S. R. De Mattos ◽  
M. A. Del Lama ◽  
R. H. Toppa ◽  
A. R. Arno Rudi Schwantes
Keyword(s):  
Total Sample ◽  
Electrophoretic Analysis ◽  
Genetic Distances ◽  
Population Subdivision ◽  
Plasma Samples ◽  
Free Living ◽  
Paulo State ◽  
Genotype Frequencies ◽  
Chrysocyon Brachyurus ◽  
F Statistics

Electrophoretic analysis of presumptive twenty gene loci products was conducted in hemolisates and plasma samples of twenty-eight maned wolves (Chrysocyon brachyurus) from an area in northeastern São Paulo State, Brazil. The area sampled was divided into three sub-areas, with the Mogi-Guaçu and Pardo rivers regarded as barriers to the gene flow. The polymorphism degree and heterozygosity level (intralocus and average) estimated in this study were similar to those detected by other authors for maned wolves and other species of wild free-living canids. The samples of each sub-area and the total sample exhibited genotype frequencies consistent with the genetic equilibrium model. The values of the F-statistics evidenced absence of inbreeding and population subdivision and, consequently, low genetic distances were found among the samples of each area.

Speciation in Sapsuckers (Sphyrapicus): I. Genetic Differentiation

The Auk ◽  
1983 ◽  
Vol 100 (4) ◽  
pp. 871-884 ◽  
Author(s):  
Ned K. Johnson ◽  
Robert M. Zink
Keyword(s):  
Genetic Information ◽  
Common Ancestor ◽  
Electrophoretic Analysis ◽  
Genetic Distances ◽  
Mean Value ◽  
Biological Species ◽  
Population Subdivision ◽  
Separate Species ◽  
Sister Clade ◽  
The Mean

Abstract We report the results of an electrophoretic analysis at 39 presumptive genetic loci of 88 specimens in the picid genus Sphyrapicus, here treated as comprising the following species: Williamson's Sapsucker (S. thyroideus), Yellow-bellied Sapsucker (S. varius), Red-naped Sapsucker (S. nuchalis), and Red-breasted Sapsucker (S. ruber). Seventeen loci (43.5%) were polymorphic. Values for observed heterozygosity in S. ruber ruber, S. ruber daggetti, and in three populations of S. nuchalis were uniform and averaged 0.043, the mean value reported for other birds. However, S. varius, at 0.022, and S. thyroideus, at 0.016, have low values of H. Values for percentage of polymorphic loci ranged from 12.8 to 20.5 in S. ruber and S. nuchalis, 12.8 in S. varius, and 7.7 in S. thyroideus. In contrast, all four species exhibited a similar mean number of alleles per locus (1.12-1.21). Genetic distances between populations of the same species are either very low or zero. Genetic distances are also very low between the phenotypically dissimilar ruber and nuchalis (D̄ = 0.004), two forms we consider to be biological species based on their assortative mating in sympatry. This is the lowest avian interspecific D-value ever reported and is similar to that found between avian subspecies. Phenotypically, varius and nuchalis are very similar, yet the average genetic distance between samples of these forms, 0.029, is comparable to interspecific values reported for other avian congeners and is our chief basis for treating the two forms as separate species. S. thyroideus is strongly differentiated genetically from varius (D̄ = 0.142), from nuchalis (D̄ = 0.197), and from ruber (D̄ = 0.186). FST statistics point to little or no population subdivision within ruber and nuchalis but substantial subdivision within the superspecies varius (S. varius + S. nuchalis + S. ruber). The genetic information suggests that the Williamson's Sapsucker represents the oldest lineage in the genus. S. thyroideus split from its sister clade (superspecies S. varius) between 3 and 4 MYBP. S. ruber and S. nuchalis are sister species that evolved very recently, either during or since the Pleistocene and sometime after their common ancestor diverged from S. varius.

Diversity of Washoe pine and comparisons with allozymes of ponderosa pine races

1990 ◽  
Vol 20 (3) ◽  
pp. 298-308 ◽  
Author(s):  
Charles R. Niebling ◽  
M. Thompson Conkle
Keyword(s):  
Genetic Distance ◽  
Great Basin ◽  
Ponderosa Pine ◽  
Rocky Mountain ◽  
Electrophoretic Analysis ◽  
Allozyme Variation ◽  
Genetic Distances ◽  
Isolated Populations ◽  
The North ◽  
The Pacific

Washoe pine (Pinuswashoensis Mason and Stockwell), a narrow endemic native to mountains on the western rim of the Great Basin in northeastern California and northwestern Nevada, may be on the verge of extinction. Lowered genetic diversity and increased interpopulation differentiation are expected evolutionary consequences for small, isolated populations like those of Washoe pine. But the species has levels of allozyme variation (estimated average heterozygosity for 26 loci equals 0.148) similar to those for widespread geographic races of ponderosa pine (Pinusponderosa Laws.), which are likely to be its closest extant relatives. Heterozygosity in ponderosa pine was 0.144 in the Pacific race, 0.178 in the North Plateau race, and 0.164 in the Rocky Mountain race. Electrophoretic analysis of trees in the three well-documented populations of Washoe pine revealed only minor and nonsignificant population to population differentiation (98.4% of allozyme variation was among samples within populations). Pair-wise genetic distances between the Washoe populations and the three northern races of ponderosa pine indicated that its closest similarity was with the North Plateau race (Nei's unbiased genetic distance averaged 0.004); the next closest similarity was with samples of the Pacific race (genetic distance 0.013). Washoe pine and the Pacific and North Plateau races of ponderosa pine were all strongly differentiated from the Rocky Mountain race of ponderosa pine (genetic distances were 0.066, 0.082, and 0.060, respectively. The few remaining populations of Washoe pine may be a potentially valuable gene source for the yellow pines of North America.

The cytology of hybrids between Hordeum vulgare and H. bulbosum revisited

Genome ◽  
1988 ◽  
Vol 30 (4) ◽  
pp. 486-494 ◽  
Author(s):  
Xu Jie ◽  
J. W. Snape
Keyword(s):  
Hordeum Vulgare ◽  
High Frequency ◽  
Interspecific Hybrids ◽  
Somatic Chromosome ◽  
Banding Technique ◽  
Chromosome 6 ◽  
Hordeum Bulbosum ◽  
Chromosome Counts ◽  
Low Frequencies ◽  
C Banding

Diploid and triploid interspecific hybrids were produced from crosses between four Hordeum vulgare varieties and two diploid and two tetraploid Hordeum bulbosum genotypes. These were studied cytologically using a C-banding technique as well as with conventional staining procedures. C-banding of mitotic preparations of the hybrids enabled all H. vulgare chromosomes to be identified individually, although only the satellited chromosome of H. bulbosum could be distinguished from the others of this genome. Most diploid hybrids had stable somatic chromosome constitutions (2n = 14), although 4 out of 39 plants had a mosaic constitution. Chromosome counts of triploid hybrids, however, revealed that about 40% of plants had a mosaic somatic constitution ranging from 7–22 chromosomes per cell, although 21-chromosome cells were at the highest frequency. Studies of meiosis in diploid hybrids showed that the frequency of pairing between H. vulgare and H. bulbosum chromosomes varied between different cross combinations and appeared to be mainly under the control of the H. bulbosum genome. C-banding revealed that H. vulgare chromosome 6 paired with the satellited chromosome of H. bulbosum. However, this latter chromosome was also absent in the majority of aneuploid cells and appeared to be the first to be eliminated. Meiosis in triploid hybrids was characterized by the presence of univalents, bivalents, and trivalents and, infrequently, higher order associations. Bivalents were formed mainly from pairing between H. bulbosum chromosomes alone, although trivalents were formed from pairing between two H. bulbosum and one H. vulgare chromosomes. All univalents, in cells that contained less than seven, were H. vulgare chromosomes. Overall, these results indicate that a high frequency of homoeologous allosyndesis can occur between the chromosomes of these two species, but it does depend on the H. bulbosum genotype used. It should be possible to introgress genes into H. vulgare through the use of H. bulbosum genotypes that have low frequencies of elimination and high chromosome pairing.Key words: Hordeum vulgare, H. bulbosum, C-banding, chromosome pairing.

scholarly journals Flexible methods for estimating genetic distances from nucleotide data

2014 ◽  
Author(s):  
Simon Joly ◽  
David J Bryant ◽  
Peter J Lockhart
Keyword(s):  
Evolutionary Biology ◽  
Massively Parallel Sequencing ◽  
Allelic Variation ◽  
Gene Dosage ◽  
Genetic Distances ◽  
Distance Measures ◽  
Rate Variation ◽  
Nucleotide Polymorphisms ◽  
Nucleotide Data ◽  
Variance Estimates

With the increasing use of massively parallel sequencing approaches in evolutionary biology, the need for fast and accurate methods suitable to investigate genetic structure and evolutionary history are more important than ever. We propose new distance measures for estimating genetic distances between individuals when allelic variation, gene dosage and recombination could compromise standard approaches. We present four distance measures based on single nucleotide polymorphisms (SNP) and evaluate them against previously published measures using coalescent- based simulations. Simulations were used to test (i) whether the measures give unbiased and accurate distance estimates, (ii) whether they can accurately identify the genomic mixture of hybrid individuals and (iii) whether they give precise (low variance) estimates. The effect of rate variation among genes and recombination was also investigated. The results showed that the SNP-based GENPOFAD distance we propose appears to work well in the widest range of circumstances. It was the most accurate and precise method for estimating genetic distances and is also relatively good at estimating the genomic mixture of hybrid individuals. Our simulations provide benchmarks to compare the performance of different method that estimate genetic distances between organisms.

Genome constitution and reproductive biology of hybrid salamanders, genus Ambystoma, on Kelleys Island in Lake Erie

1987 ◽  
Vol 65 (9) ◽  
pp. 2188-2201 ◽  
Author(s):  
James P. Bogart ◽  
Leslie A. Lowcock ◽  
Clifford W. Zeyl ◽  
Barbara K. Mable
Keyword(s):  
Lake Erie ◽  
Valid Species ◽  
Ambystoma Tigrinum ◽  
Starch Gel Electrophoresis ◽  
Genome Composition ◽  
Chromosome Counts ◽  
Hybrid Female ◽  
Breeding Sites ◽  
Ambystoma Laterale ◽  
Starch Gel

On Kelleys Island, Ohio, in Lake Erie, are found bisexual Ambystoma tigrinum and Ambystoma texanum as well as five different combinations of diploid and polyploid hybrid female salamanders. Genome composition and ploidy of salamanders from five breeding sites on the island were examined using starch gel electrophoresis, erythrocyte area measurements, and chromosome counts. All of the hybrids contained at least one Ambystoma laterale genome, yet pure individuals of this species were not encountered. Embryonic mortality was severe among eggs deposited by 42 hybrid females. The few resulting offspring, when compared electrophoretically with their mothers, showed no evidence of being the product of parthenogenesis. Recently described Ambystoma nothagenes Kraus is not a valid species as this trihybrid is demonstrated to be genetically heterogeneous and independently derived from diploid A. laterale × texanum hybrids.

Growth and sexual maturation in diploid and polyploid salamanders (genus Ambystoma)

1989 ◽  
Vol 67 (4) ◽  
pp. 812-818 ◽  
Author(s):  
Lawrence E. Licht ◽  
James P. Bogart
Keyword(s):  
Larval Development ◽  
Sexual Maturation ◽  
Sexual Maturity ◽  
Initial Study ◽  
Reproductive Patterns ◽  
Laboratory Conditions ◽  
Total Length ◽  
Ambystoma Laterale ◽  
Ambystoma Texanum

On Pelee Island, Ontario, mole salamanders, Ambystoma laterale and Ambystoma texanum, coexist with their diploid, triploid, and tetraploid hybrids. In an initial study, A. laterale and hybrid larvae were raised in groups, but from metamorphosis to 5 months postmetamorphosis, individuals were raised in isolation. In a second study, A. texanum and hybrids were raised as isolated individuals under uniform feeding and laboratory conditions from the egg stage to 22 months postmetamorphosis. The total length of larvae at 14 days posthatching was correlated with size of eggs. Tetraploids originated from larger eggs, were larger at 2 weeks posthatching, and maintained their larger size throughout larval development. Tetraploids metamorphosed later and were heavier than all other genotypes. The heavier mass at metamorphosis was maintained and relatively increased so that by 22 months postmetamorphosis, when compared with other groups, tetraploids were heavier in mass, but not larger in snout–vent length. Bodies of tetraploids were more robust and tails, although not longer, were thicker. In contrast to A. texanum and diploid and triploid hybrids, among which 50% of individuals developed fully pigmented, yolk-filled ova by 22 months, no tetraploids showed such signs of sexual maturity. The growth and reproductive patterns of diploids and polyploids are discussed.

scholarly journals Clarifying Taxonomy and Nomenclature of Fothergilla (Hamamelidaceae) Cultivars and Hybrids

HortScience ◽  
2007 ◽  
Vol 42 (3) ◽  
pp. 470-473 ◽  
Author(s):  
Thomas G. Ranney ◽  
Nathan P. Lynch ◽  
Paul R. Fantz ◽  
Paul Cappiello
Keyword(s):  
Interspecific Hybrids ◽  
Morphological Characteristics ◽  
Correct Classification ◽  
Chromosome Counts ◽  
Latin Diagnosis ◽  
Dna Contents ◽  
Garden Plants ◽  
Clear Differentiation

Fothergilla L. spp. are valuable nursery and garden plants. However, clear differentiation among F. gardenii Murray, F. major Lodd., and potential hybrids can be difficult based solely on morphological characteristics. The objectives of this work were to verify and describe the existence of interspecific hybrids and to clarify the proper nomenclature for cultivars of Fothergilla that are commonly grown in the nursery industry. A comparison of morphological characteristics was made among diverse clones representing both species and potential hybrids. A combination of chromosome counts and DNA contents was used to clearly differentiate among F. gardenii (2n = 4x = 48), F. major (2n = 6x = 72), and hybrids (2n = 5x = 60). It was determined that the majority of cultivars represented in commerce were hybrids. Fothergilla ×intermedia Ranney and Fantz (hybrid fothergilla) is proposed as the name for these hybrids and is validated with a Latin diagnosis. Although certain morphological characteristics can be used to differentiate between F. gardenii and F. major, the hybrids tend to be intermediate and are particularly difficult to separate from F. major on the basis of appearance. The correct classification and nomenclature for 17 different taxa are presented.

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