Morphometric variation of wild trout populations from northwestern Mexico (Pisces: Salmonidae)

Morphometric variation of 17 wild troutpopulations of the genus Oncorhynchusfrom northwestern Mexico was analyzed.We used 25 standardized morphometric characters following a box truss protocol. In thediscriminant function analysis (DFA) of theexamined specimens (n = 214), grouped bydrainage, the canonical root 1 explained 88.1%of the total variation. Sixteen linearcharacters allow distinguishing O. mykissnelsoni (Sierra San Pedro Mártir [SSPM])from O. chrysogaster and O. mykisssspp. (Sierra Madre Occidental [SMO]). Twodistinctive groups of populations wererecognized on the basis of the squaredMahalanobis' distances, one for the SSPM (O. m. nelsoni) and the other for the SMO. Thelatter group is divided into four subgroups:(1) O. chrysogaster (Río Fuerte andRío Culiacán) and O. mykiss ssp.(Río Piaxtla); (2) O. mykiss sspp.(Río San Lorenzo, Río Baluarte, andRío Acaponeta); (3) O. mykiss sspp.(Río Yaqui and Río Mayo); and (4) O. chrysogaster (Río Sinaloa). In the DFAamong populations within each taxon, thecanonical variable 1 accounted for 41.8% ofthe total variation for O. m. nelsoni,59.4% for O. chrysogaster, and 43.8%for O. m. sspp.     

Mitochondrial DNA Diversity and Genetic Differentiation of the Honeybee (Apis cerana) in Thailand

Genetic diversity of the honeybee (Apis cerana) in Thailand collected from north, northeast, the central region, peninsular Thailand, and Samui Island (n = 181) was examined by PCR–RFLP of ATPase6–ATPase8. Interestingly, 78 individuals (43.09%) of the southern-latitude bees exhibited length heteroplasmy of the PCR product. The gel-eluted ATPase6–ATPase8 (825 bp) of each bee was restricted with TaqI, SspI, and VspI, respectively. Eight mitotypes were generated and revealed biogeographic differentiation between conspecific samples of A. cerana. AAA, ACA, AAD, BAA, ADA, and ABA were found only in the north-to-central samples (north, northeast, and central region); BBB and BBC were found in the southern-latitude bees; and BBC was restrictively found in the Samui sample. Large genetic distances were observed between each of the north-to-central samples and peninsular Thailand and Samui samples, but lower levels of genetic distance were found within each region. Geographic heterogeneity and phylogenetic analyses indicated that Thai A. cerana could be genetically differentiated into northern Thailand, peninsular Thailand, and Samui Island populations.     

Genetic Structure and Low-genetic Diversity Suggesting the Necessity for Conservation of the Chinese Longsnout Catfish, Leiocassis longirostris (Pisces: Bagriidae)

Synopsis Genetic variation and phylogenetic relationship of Leiocassis longirostris populations from the Yangtze River were investigated at mitochondrial DNA level. The samples were collected from the upstream and mid-downstream of the Yangtze River. Three mitochondrial DNA fragments, ND5/6, cytochrome b (Cyt b) and control region (D-loop), were amplified and then digested by 10 restriction endonucleases. Twenty-three D-loop fragments randomly selected were sequenced. Digestion patterns of ND5/6 by AluI and HaeIII, D-loop by HinfI and RsaI, and Cyt b by HaeIII were polymorphic. Ten and eighteen haplotypes were obtained from RFLP data and sequence data, respectively. The individuals from upstream and mid-downstream of the Yangtze River were apparently divided into two groups. The average genetic distance was 0.008 and 0.010 according to the two data. Low diversities and decreasing abundance indicated that Leiocassis longirostris may be in severe danger and reasonable measures of fishery management should be taken.     

Mitochondrial genome diversity among cultivars of daucus carota (ssp. sativus) and their wild relatives

Summary Restriction fragment patterns of mitochondrial DNAs (mtDNAs) from 13 carrot cultivars (Daucus carota ssp. sativus), wild carrot (ssp. carota), ssp. gummifer, and D. capillifolius were compared with each other using four restriction endonucleases. The mtDNAs of the 13 carrot cultivars could be classified into three distinct types — I, II and III — and were also clearly distinguishable from the mtDNAs of wild carrot (type IV), gummifer (V) and D. capillifolius (VI). The proportions of common restriction fragments (F values) shared by two of the three mtDNA types (I, II and III) of carrot cultivars were approximately 0.5–0.6. The F values were 0.4–0.5 for mitochondrial genomes between wild carrot, ssp. gummifer and D. capillifolius. The mitochondrial genomes between wild carrot and the carrot cultivars showed closer homologies those between wild carrot, ssp. gummifer, and D. capillifolius. The diversity of the mitochondrial genomes among the carrot cultivars is too high to presume that it was generated from the cytoplasm of only one common ancestor during the relatively short history of carrot breeding. These results suggested that the three types of cytoplasms found in the carrot cultivars might have existed in a prototype of D. carota in pre-historical times.     

Heritable somaclonal variation in wild barley (Hordeum spontaneum)

Summary Progenies of H. spontaneum plants regenerated from immature embryo derived calli were analysed for somaclonal variation on the following traits: (1) organization of the intergenic spacer of the rRNA genes; (2) B and C hordein pattern on SDS-PAGE; (3) genomic organization of the B and C hordein coding sequences; (4) mitochondrial DNA organization assayed by hybridization of Southern blots of total DNA with mitochondrial coding genes; (5) cytology. One out of twelve progeny plants was characterized as variant for two traits: (a) a loss of 1.8 and 2.5 kb Taq I intergenic rDNA spacer fragments and (b) a variant pattern of hordeins on 1-D SDS-PAGE. No numerical or structural chromosome variation was detected among the control plants therefore it is assumed that the variation was caused by the in vitro culture and transmitted, through sexual reproduction, to the analysed progeny.     

Phylogeographic structure of brown trout Salmo trutta in Britain and Ireland: glacial refugia,postglacial colonization and origins of sympatric populations

The phylogeographical structure of brown trout Salmo trutta in Britain and Ireland was studied using polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) analysis of four mitochondrial DNA segments (16S/ND1, ND5/6, COXIII/ND5 and ND5/12S). Analysis of 3636 individuals from 83 sites–morphotypes revealed a total of 25 haplotypes. These haplotypes were nested in seven two‐step clades. Although there was a clear geographical patterning to the occurrence of derived clades, admixture among ancestral clades was extensive throughout the studied area. A relevant feature of the data was that some populations contained mixtures of highly divergent clades. This type II phylogeographic pattern is uncommon in nature. Clade intermixing is likely to have taken place during earlier interglacials as well as since the Last Glacial Maximum. The anadromous life history of many S. trutta populations has probably also contributed to clade mixing. Based on the data presented here and published data, postglacial colonization of Britain and Ireland most likely involved S. trutta from at least five potential glacial refuges. Probable locations for such refugia were: south of England–western France, east of the Baltic Sea, western Ireland, Celtic Sea and North Sea. Ferox S. trutta, as defined by their longevity, late maturation and piscivory, exhibited a strong association with a particular clade indicating that they share a common ancestor. Current evidence indicates that the Lough Melvin gillaroo S. trutta and sonaghen S. trutta sympatric types diverged prior to colonization of Lough Melvin and, although limited gene flow has occurred since secondary contact, they have remained largely reproductively isolated due to inlet and outlet river spawning segregation. Gillaroo S. trutta may reflect descendents of a previously more widespread lineage that has declined due to habitat alterations particularly affecting outlet rivers. The mosaic‐like distribution of mtDNA lineages means that conservation prioritization in Britain and Ireland should be based on the biological characteristics of local populations rather than solely on evolutionary lineages.     

Mitochondrial DNA variation in bull trout (Salvelinus confluentus) from northwestern North America: implications for zoogeography and conservation

Bull trout, Salvelinus confluentus (Salmonidae), are distributed in northwestern North America from Nevada to Yukon Territory, largely in interior drainages. The species is of conservation concern owing to declines in abundance, particularly in southern portions of its range. To investigate phylogenetic structure within bull trout that might form the basis for the delineation of major conservation units, we conducted a mitochondrial DNA (mtDNA) survey in bull trout from throughout its range. Restriction fragment length polymorphism (RFLP) analysis of four segments of the mtDNA genome with 11 restriction enzymes resolved 21 composite haplotypes that differed by an average of 0.5% in sequence. One group of haplotypes predominated in 'coastal' areas (west of the coastal mountain ranges) while another predominated in 'interior' regions (east of the coastal mountains). The two putative lineages differed by 0.8% in sequence and were also resolved by sequencing a portion of the ND1 gene in a representative of each RFLP haplotype. Significant variation existed within individual sample sites (12% of total variation) and among sites within major geographical regions (33%), but most variation (55%) was associated with differences between coastal and interior regions. We concluded that: (i) bull trout are subdivided into coastal and interior lineages; (ii) this subdivision reflects recent historical isolation in two refugia south of the Cordilleran ice sheet during the Pleistocene: the Chehalis and Columbia refugia; and (iii) most of the molecular variation resides at the interpopulation and inter-region levels. Conservation efforts, therefore, should focus on maintaining as many populations as possible across as many geographical regions as possible within both coastal and interior lineages.     

Chromosome painting supports lack of homology among sex chromosomes in Oncorhynchus, Salmo, and Salvelinus (Salmonidae)

The sex chromosome pair has been identified previously as the largest submetacentric pair in the genome in several species of the genus Salvelinus (eastern trouts and chars) including S. namaycush (lake trout) and as a large subtelocentric/acrocentric pair in several species of the genus Oncorhynchus (Pacific trouts and salmon). Sex chromosomes have not been identified in Salmo (Atlantic salmon and brown trout). Two paint probes, one specific for the short arm (Yp) and the other for the long arm (Yq) of the sex chromosome pair in Salvelinus namaycush were hybridized to chromosomes of Oncorhynchus mykiss (rainbow trout) and O. tshawytscha (chinook salmon) and Salmo salar (Atlantic salmon) and S. trutta (brown trout). The two probes hybridized to two different autosomal pairs in each of the Oncorhynchus species, supporting lack of homology between the sex chromosomes in the two genera. The Yp probe hybridized to interstitial regions on two different chromosome pairs in S. salar and one pair in S. trutta. The Yq probe hybridized to a different pair in both species.     

Physalis (Solanaceae) and allied genera: Tzeltalia, a new genus from the highlands of southern Mexico and northwestern Guatemala

A morphological analysis ofPhysalis and several closely related genera, with emphasis on a group of species known as “atypicalPhysalis,” showed that two of the atypical species are better treated as a distinct genus.Tzeltalia is described and two new combinations are made:T. amphitricha andT. calidaria. Restricted to the highlands of Chiapas, Mexico, and adjacent Guatemala,Tzeltalia is distinguished fromPhysalis by a combination of characters including shrubby habit; fasciculate flowers; lobed corolla; scabrate pollen; and non-invaginated, partially open, coriaceous, and reticulate-veined fruiting calyx.

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Resumen  El análisis de un grupo de especies atípicas dePhysalis y otros géneros relacionados demostró que dos especies deben considerarse como otro género. Se describeTzeltalia, un género restringido a los altos de Chiapas, México, y Guatemala y se hacen dos nuevas combinaciones,T. amphitricha yT. calidaria.Tzeltalia se distingue dePhysalis por una combinación de caracteres que incluyen un habito arbustivo, flores fasciculadas, corola lobulada, polen escabroso, cáliz del fruto no invaginado, parcialmente abierto, coriáceo y con venación reticulada.

     

Genetic diversity of Garra rufa Heckel, 1843 (Teleostei: Cyprinidae) in Anatolia

In the present study, mitochondrial DNA polymerase chain reaction-restriction-fragment length polymorphism (PCR-RFLP) and nuclear DNA inter-simple sequence repeat (ISSR) assays were used to assess the phylogenetic and phylogeographic relationships among Garra rufa samples from Anatolia. The complete mtDNA NADH 3/4 dehydrogenase (ND-3/4) gene amplified by PCR was digested with eight restriction enzymes. These enzymes produced 20 composite haplotypes for G. rufa populations. All the mtDNA haplotypes detected were highly diverged from each other and each lineage had a unique genetic profile. The evaluation of mtDNA PCR-RFLP data coupled with geological history of Anatolia indicated a deep genetic divergence among the mtDNA haplotypes of G. rufa populations from drainages of the Mediterranean and Persian Gulf, suggesting an early isolation of Tigris-Euphrates with Orontes river and other rivers draining into the Mediterranean Sea. In general, data from both mtDNA and nDNA were congruent.     

Mitochondrial DNA diversity and male sterility in natural populations of Daucus carota ssp carota

Mitochondrial variability was investigated in natural populations of wild carrot (Daucus carota ssp carota) in different regions: South of France, Greece, and various sites in the Mediterranean Basin and Asia. Total DNA was digested with two restriction endonucleases (EcoRV and HindIII) and probed with three mitochondrial DMA-specific genes (coxI, atp6, and coxII). Twenty-five different mitochondrial types were found in 80 analyzed individuals. Thirteen mitotypes were found among the 7 French populations studied. On average, 4.4 different mitotypes were observed per population, and these mitotypes were well-distributed among the populations. All of the mitochondrial types were specific to a single region. However, the proportion of shared restriction fragments between 2 mitotypes from different regions was not particularly lower than that which occurred among mitotypes from a single region. On the basis of the sexual phenotype [male-sterile (MS) or hermaphrodite] of the plants studied in situ and that of their progeny, 2 mitotypes were found to be highly associated with male sterility. Eighty percent of the plants bearing these mitotypes were MS in situ, and all of these plants produced more than 30% MS plants in their progeny. This association with male sterility was consistent in several populations, suggesting an association with a cytoplasmic male-sterility system. Moreover, these two mitotypes had very similar mitochondrial DNA restriction patterns and were well-differentiated from the other mitotypes observed in wild plants and also from those observed in the two CMS types already known in the cultivated carrot. This suggests that they correspond to a third cytoplasmic sterility.     

Mitochondrial haplotype variability of brown trout populations from Northwestern Iberian Peninsula,a secondary contact area between lineages

Previous studies using mitochondrial markers and microsatellites revealed a new highly differentiated Atlantic lineage of brown trout in the Iberian Peninsula mainly confined to the Upper Duero Basin. Data suggest that Duero lineage (DU) hybridizes with previously described Atlantic (AT) lineages in that basin. However, nuclear and cytogenetic data suggest another hybrid zone between divergent lineages might be present in the Miño Basin, another Atlantic drainage located to the north. Here, we extend those studies by analyzing the mitochondrial haplotype variability of brown trout populations from northwestern Spain, a poorly studied area, to obtain an accurate picture of the distribution of DU. Results show that the DU haplotype is fixed in several isolated populations from the upper course of the Miño River and its main tributary the Sil River. DU haplotype co-occurs with two related AT haplotypes in the Miño Basin revealing a new secondary contact zone. The identification of both longtime stable populations of DU and several other populations showing introgression with widespread AT lineages will be useful for the management and conservation of such an endemic lineage.     

Mitochondrial DNA variation in pearl millet and related species

Summary Mitochondrial DNA (mtDNA) restriction endonuclease fragment patterns and patterns of mtDNA hybridized by mitochondrial gene probes were used to study phylogenetic relationships of seven Pennisetum species, including five P. americanum (pearl millet) ecotypes and a reference species from the distantly related genus, Panicum. The restriction patterns of the pearl millet ecotypes were uniform with the exception of the ecotype collected in Ethiopia. The probe hybridization method revealed more variability, with both the Rhodesian and Ethiopian ecotypes differing from the others and from each other. Considerable restriction pattern polymorphism was noted among different species of Pennisetum, and Panicum. Significant relationships were noted of Pennisetum polystachyon to P. pedicellatum and of P. purpureum to P. squamulatum using the restriction pattern method. In addition to those relationships, the hybridization method showed relationships of pearl millet to P. purpureum and to P. squamulatum. The relationships noted between species by the hybridization method agreed more closely to the cytological data than those indicated by the restriction pattern method. Therefore, the hybridization method appeared to be the preferred method for studying species relationships. The mitochondrial genome size of pearl millet was calculated to be 407 kb and the mitochondrial genome sizes of other Pennisetum species ranged from 341 to 486 kb.Florida Agricultural Experiment Station Journal Series No. 8485.     

Restriction fragment length polymorphism (RFLP) of wild perennial relatives of soybean

Summary Total DNA from callus tissue of 28 accessions representing seven wild perennial Glycine species was compared using recombinant genomic probes derived from G. max, the soybean. Using two probes, we show that this molecular approach both confirms and extends the model for the taxonomic relationships between the species derived from morphological and cytogenetic data, and that it provides clear evidence that RFLP analysis of genomic sequences has the potential for revealing the derivation of the member species of the wild perennial Glycine taxon. Although, in this preliminary report, the sample size for each species is small, it is clear that the greatest between-accession variation occurs in G. tabacina (B₂B₂) and G. clandestine (A₁A₁), suggesting that these may be the taxa from which further speciation occurred in the subgenus.     

Ten new species of Tibouchina (Melastomataceae) from Mexico

Ten new species of Tibouchina (T. almedae, T. congestiflora, T. connata, T. hintonii, T. macvaughii, T. nanifolia, T. patens, T. roseotincta, T. sinaloensis, andT. thulia) are described from western Mexico. Distinguishing characteristics, phenology, distribution, and phylogenetic relationships are discussed. Illustrations of all these new species are provided.     

Three new species of Spigelia (Strychnaceae) from Mexico

During a revisionary study ofSpigelia, three new species from Mexico were discovered. Two of these new species appear to be narrow endemics, one in the state of Chiapas and one in the state of Guerrero, and the third is more widespread in Mexico and Guatemala. These new species are described, illustrated, and distinguished from other North AmericanSpigelias.     

Three new species of Ocotea (Lauraceae) from southern Mexico

Three new species ofOcotea (O. disjuncta, O. iridescens, andO. rovirosae) from southern Mexico are described and illustrated.Ocotea disjuncta is related to theO. effusa group, whileO. iridescens seems to be related to theO. heydeana group. The relationships ofO. rovirosae are not clear.      

Mitochondrial DNA variation and crossability of leek (Allium porrum) and its wild relatives from the Allium ampeloprasum complex

 Mitochondrial (mt) DNA variation in the cultigens leek, kurrat and prei-anak is limited compared to that of their wild relatives in the Allium ampeloprasum complex. The phylogenetic relationships among these cultigens and their wild relatives is quite close, with the majority of the species clustering within one mitochondrial clade. The presence in leek of an extra-mitochondrial genetic element was noted. Analysis of crossability showed that all species were interfertile with leek. It is suggested that the genetic variation present within the A. ampeloprasum complex could be exploited in order to broaden the genetic basis of leek. Received: 14 August 1996 / Accepted: 23 August 1996