Incomplete reproductive isolation and strong transcriptomic response to hybridization between sympatric sister species of salmon.

Global change is altering ecosystems at an unprecedented rate. The resulting shifts in species ranges and reproductive timing are opening the potential for hybridization between closely related species which could dramatically alter the genetic diversity, adaptive capacity and evolutionary trajectory of interbreeding taxa. Here, we used behavioural breeding experiments, in vitro fertilization experiments, and whole-transcriptome gene expression data to assess the potential for and consequences of hybridization between Chinook and Coho salmon. We show that behavioural and gametic prezygotic barriers between socio-economically valuable Chinook and Coho salmon are incomplete. Postzygotically, we demonstrate a clear transcriptomic response to hybridization among F1 Chinook-Coho offspring. Genes transgressively expressed within hybrids were significantly enriched with genes encoded in the nucleus but localized to the mitochondrion, suggesting a potential role for mito-nuclear incompatibilities as a postzygotic mechanism of hybrid breakdown. Chinook and Coho salmon are expected to continue to respond to climate change with shifts in migration timing and habitat use, potentiating hybridization between these species. The downstream consequences of hybridization on the future of these threatened salmon, and the ecosystems they inhabit, is unknown.

Growth and endocrine effect of growth hormone transgene dosage in diploid and triploid coho salmon.

Growth-hormone transgene dosage, polyploidy, and parental effects on growth and endocrine responses have been assessed in coho salmon. Diploid fry with one or two transgene doses grew equally, whereas later-stage juvenile homozygotes grew faster than hemizygotes. In contrast, homozygotes and hemizygotes grew equally after smoltification, both in sea water and fresh water. Triploid transgenic salmon showed impaired growth which could not be fully overcome with additional transgene copies. Levels of muscle GH mRNA were elevated in two vs. one transgene dose diploids, but in triploids, a dosage effect was observed in muscle but not for animals carrying three transgene doses. IGF-I mRNA levels were elevated in transgenic vs. non-transgenic animals, but a dosage effect was not observed. Diploids and triploids with two transgenes had higher plasma GH levels than one-dose animals, but three-dose triploids showed no further elevation. Circulating IGF-I levels also showed a dosage effect in diploids, but not among any transgene doses in triploids. The present study reveals complex interactions among transgene dosage, maternal effects, developmental stage, and ploidy on growth and endocrine parameters in GH transgenic coho salmon. Specifically, GH transgenes do not always express nor have effects on growth that are directly correlated with the number of transgenes. Further, the reduced growth rate seen in triploid transgenic animals could not be fully overcome by increasing transgene dosage. The findings have relevance for understanding growth physiology, transgene function, and for environmental risk assessments that require understanding phenotypes of hemizygous vs. homozygous transgenic animals in populations.

Y-chromosomal DNA markers for discrimination of chemical substance and effluent effects on sexual differentiation in salmon.

Chinook salmon alevins were exposed during their labile period for sex differentiation to different concentrations of bleached kraft mill effluent (BKME), primary sewage effluent, secondary sewage effluent (SE), 17ss-estradiol, testosterone, and nonylphenol. After exposure for 29 days post hatching (DPH), fish were allowed to grow until 103 and 179 DPH, at which time their genetic sex was determined using Y-chromosomal DNA markers and their gonadal sex was determined by histology. Independent of treatment, all fish identified as genetic females (XX) in these experiments possessed normal female gonads. Only the highest dose of some treatments affected the development of gonads in genetic XY males. At 103 DPH, some genetic males treated with 1 micro g estradiol/L, BKME 100%,and SE 30% developed as physiological females, presenting ovaries identical to genetic females in the control group. The physiological female condition in XY fish was also observed in these treatments groups at 179 DPH, which suggests that the effect is permanent, whereas in other groups the effect changed between sampling periods. Identification of the genetic sex of individual animals using sex-linked DNA markers provides a useful tool for investigating environmental factors influencing sex determination and differentiation.

Rhodium cluster complexes containing bridging phenylgermanium ligands.

The reaction of Rh(4)(CO)(12) with Ph(3)GeH at 97 degrees C has yielded the first rhodium cluster complexes containing bridging germylene and germylyne ligands: Rh(8)(CO)(12)(mu(4)-GePh)(6), 9, and Rh(3)(CO)(5)(GePh(3))(mu-GePh(2))(3)(mu(3)-GePh)(mu-H), 10. When the reaction is performed under hydrogen, the yield of 9 is increased to 42% and no 10 is formed. Compound 9 contains a cluster of eight rhodium atoms arranged in the form of a distorted cube. There are six mu(4)-GePh groups bridging each face of this distorted cube. Four of the rhodium atoms have two terminal carbonyl ligands, while the remaining four rhodium atoms have only one carbonyl ligand. Compound 10 contains a triangular cluster of three rhodium atoms with one terminal GePh(3) ligand, three bridging GePh(2) ligands, and one triply bridging GePh ligand. There is also one hydrido ligand that is believed to bridge one of the Rh-Ge bonds. Compound 9 reacted with PPhMe(2) at 25 degrees C to give the tetraphosphine derivative Rh(8)(CO)(8)(PPhMe(2))(4)(mu(4)-GePh)(6), 11. The structure of 11 is similar to 9 except that a PPhMe(2) ligand has replaced a carbonyl ligand on each the four Rh(CO)(2) groups. Compound 10 reacted with CO at 68 degrees C to give the complex Rh(3)(CO)(6)(mu-GePh(2))(3)(mu(3)-GePh), 12. Compound 12 is formed by the loss of the hydrido ligand and the terminal GePh(3) ligand from 10 and the addition of one carbonyl ligand. All compounds were fully characterized by IR, NMR, elemental, and single-crystal X-ray diffraction analyses.

High-nuclearity iridium carbonyl clusters containing phenylgermyl ligands: synthesis, structures, and reactivity.

The reaction of Ir4(CO)12 with Ph3GeH at 97 degrees C has yielded the new tetrairidium cluster complexes Ir4(CO)7(GePh3)(mu-GePh2)2[mu3-eta3-GePh(C6H4)](mu-H)2 (10) and Ir4(CO)8(GePh3)2(mu-GePh2)4 (11). The structure of 10 consists of a tetrahedral Ir4 cluster with seven terminal CO groups, two bridging GePh2) ligands, an ortho-metallated bridging mu3-eta3-GePh(C6H4) group, a terminal GePh3 ligand, and two bridging hydrido ligands. Compound 11 consists of a planar butterfly arrangement of four iridium atoms with four bridging GePh2 and two terminal GePh3 ligands. The same reaction at 125 degrees C yielded the two new triiridium clusters Ir3(CO)5(GePh3)(mu-GePh2)3(mu3-GePh)(mu-H) (12) and Ir3(CO)6(GePh3)3(mu-GePh2)3 (13). Compound 12 contains a triangular Ir3 cluster with three bridging GePh2), one triply bridging GePh, and one terminal GePh3 ligand. The compound also contains a hydrido ligand that bridges one of the Ir-Ge bonds. Compound 13 contains a triangular Ir3 cluster with three bridging GePh2 and three terminal GePh3 ligands. At 151 degrees C, an additional complex, Ir4H4(CO)4(mu-GePh2)4(mu4-GePh)2 (14), was isolated. Compound 14 consists of an Ir4 square with four bridging GePh2, two quadruply bridging GePh groups, and four terminal hydrido ligands. Compound 12 reacts with CO at 125 degrees C to give the compound Ir3(CO)6(mu-GePh2)3(mu3-GePh) (15). Compound 15 is formed via the loss of the hydrido ligand and the terminal GePh3 ligand and the addition of one carbonyl ligand to 12. All compounds were fully characterized by IR, NMR, single-crystal X-ray diffraction analysis, and elemental analysis.

New rhenium-tin cluster adds palladium phosphine groups across Re-Sn bonds.

The new rhenium-tin complex Re2(CO)8(mu-SnPh2)2, 1 was obtained in 52% yield from the reaction of Re2(CO)8(mu-H)[mu-C(H)C(H)Bu] with Ph3SnH. Compound 1 contains two SnPh2 groups bridging a long Re-Re single bond, Re-Re = 3.1971(4) A [3.1902(4) A], Re-Sn = 2.7429(4) A [2.7445(4) A], and 2.7675(4) [2.7682(5) A]. A bis-Pd(PBut3) adduct of 1, Pd2Re2(CO)8(mu-SnPh2)2(PBut3)2, 2 was obtained from the reaction of 1 with Pd(PBut3)2. Compound 2 contains Pd(PBut3) groups bridging two of its four Re-Sn bonds. The Re-Re bond and the unbridged Re-Sn bonds in 2 are significantly longer than those in 1, 3.245(1) A and 2.8167(14) A, respectively. Fenske-Hall molecular orbital calculations on 1 and 2 have been performed to explain the metal-metal bonding in these unusual mixed-metal polynuclear metal complexes.

High nuclearity iridium-platinum clusters: synthesis, structures, bonding, and reactivity.

The reaction of Ir4(CO)12 with an excess of Pt(PBu(t)3)2 at room temperature yielded the bis-Pt(PBu(t)3) adduct Ir4(CO)12[Pt(PBu(t)3)]2 (9), which contains two Pt(PBu(t)3) groups bridging opposite edges of a central Ir4 pseudotetrahedron. The same reaction at 110 degrees C yielded two new higher nuclearity complexes, Ir8(CO)12[Pt(PBu(t)3)]4 (10) and Ir6(CO)10[Pt(PBu(t)3)]4 (11). Compound 10 consists of a central Ir4(CO)4 tetrahedron with four edge-bridging Ir(CO)2 groups and four Pt(PBu(t)3) groups that are each bonded to Ir3 triangles of the Ir4 tetrahedron and two of the Ir(CO)2 groups. Compound 11 consists of a central Ir4(CO)4 pseudotetrahedron with two edge-bridging Ir(CO)2 groups and four Pt(PBu(t)3) groups; one Pt(PBu(t)3) group is bonded to five iridium atoms as found in 10; two are bonded to four iridium atoms, and one is bonded to one of the outer Ir2Pt triangles. Compound 11 reacted with hydrogen at 97 degrees C to give the new tetrahydrido complex Ir6(CO)8[Pt(PBu(t)3)]4(mu-H)4 (12). Compound 12 is formed by the loss of the two bridging carbonyl ligands from 11 and the addition of four hydrido ligands. All four new compounds were characterized by both 1H and 31P NMR and by single-crystal X-ray diffraction analyses. The bonding in 9 was studied by Fenske-Hall molecular orbital calculations, which in this case provides a delocalized bonding description for the Ir-Ir and Ir-Pt bonding, where the attachment of the 0 e- fragments of Pt(PR3) use Ir-Ir bonding orbitals of the Ir4(CO)12 cluster to form multicenter Pt-Ir bonds.

Addition of palladium and platinum tri-tert-butylphosphine groups to Re-Sn and Re-Ge bonds.

The reaction of Re2(CO)8[mu-eta2-C(H)=C(H)Bu(n)](mu-H) with Ph3SnH at 68 degrees C yielded the new compound Re2(CO)8(mu-SnPh2)2 (10) which contains two SnPh2 ligands bridging two Re(CO)(4) groups, joined by an unusually long Re-Re bond. Fenske-Hall molecular orbital calculations indicate that the bonding in the Re2Sn2 cluster is dominated by strong Re-Sn interactions and that the Re-Re interactions are weak. The 119Sn Mössbauer spectrum of 10 exhibits a doublet with an isomer shift (IS) of 1.674(12) mm s(-1) and a quadrupole splitting (QS) of 2.080(12) mm s(-1) at 90 K,characteristic of Sn(IV) in a SnA2B2 environment. The IS is temperature dependent, -1.99(14) x 10(-4) mm s(-1) K(-1); the QS is temperature independent. The temperature-dependent properties are consistent with the known Gol'danskii-Kariagin effect. The germanium compound Re2(CO)8(mu-GePh2)2 (11) was obtained from the reaction of Re2(CO)8[mu-eta2-C(H)=C(H)Bu(n)](mu-H) with Ph3GeH. Compound 11 has a structure similar to that of 10. The reaction of 10 with Pd(PBu(t)3)2 at 25 degrees C yielded the bis-Pd(PBu(t)3) adduct, Re2(CO)8(mu-SnPh2)2[Pd(PBu(t)3)]2 (12); it has two Pd(PBu(t)3) groups bridging two of the four Re-Sn bonds in 10. Fenske-Hall molecular orbital calculations show that the Pd(PBu(t)3) groups form three-center two-electron bonds with the neighboring rhenium and tin atoms. The mono- and bis-Pt(PBu(t)3) adducts, Re2(CO)8(mu-SnPh2(2)[Pt(PBu(t)3)] (13) and Re2(CO)8(mu-SnPh2)2[Pt(PBu(t)3)]2 (14), were formed when 10 was treated with Pt(PBu(t)3)2. A mono adduct of 11, Re2(CO)8(mu-GePh2)2[Pt(PBu(t)3)] (15), was obtained similarly from the reaction of 11 with Pt(PBu(t)3)2.

Platinum-rhodium carbonyl clusters: new structures and new types of dynamical activity.

The reaction of Rh(4)(CO)(12) with Pt(PBu(t)(3))(2) in CH(2)Cl(2) at room temperature yielded three new complexes: Rh(4)(CO)(4)-(mu-CO)(4)(mu(4)-CO)(PBu(t)(3))(2)[Pt(PBu(t)(3))], 10, Rh(2)(CO)(8)[Pt(PBu(t)(3))](2)[Pt(CO)], 11, and Rh(2)(CO)(8)[Pt(PBu(t)(3))](3), 12. The reaction of Rh(4)(CO)(12) with an excess of Pt(PBu(t)(3))(2) in hexane at 68 degrees C yielded the new hexarhodium-tetraplatinum compound, Rh(6)(CO)(16)[Pt(PBu(t)(3))](4), 13, in a low yield. All four compounds were characterized by (31)P NMR and single-crystal X-ray diffraction analyses. Compound 10 contains an unsymmetrical quadruply bridging carbonyl ligand in the fold of a butterfly tetrahedral cluster of four rhodium atoms with a Pt(PBu(t)(3)) group bridging the hinge of the butterfly tetrahedron. Compound 11 contains an unsaturated trigonal bipyramidal Rh(2)Pt(3) cluster. Compound 12 is similar to 11 except the trigonal bipyramidal Rh(2)Pt(3) cluster opened by cleavage of one Pt-Rh bond due to steric interactions produced by the replacement of one of the carbonyl ligands in 11 with a tri-tert-butylphosphine ligand. Compound 12 undergoes facile dynamical rearrangements of the metal atoms in the cluster which average the three inequivalent phosphine ligands on the platinum atoms. Compound 13 contains an octahedral cluster of six rhodium atoms with four Pt(PBu(t)(3)) groups bridging edges of that octahedron.

Superloading of tin ligands into rhodium and iridium carbonyl cluster complexes.

The reactions of Rh4(CO)12 and Ir4(CO)12 with Ph3SnH have yielded the new Rh-Sn and Ir-Sn cluster complexes M3(CO)6(mu-SnPh2)3(SnPh3)3, 1 (M=Rh) and 2 (M=Ir). Both compounds contain triangular M3 clusters with three bridging SnPh2 and three terminal SnPh3 ligands. The M-M bonds are unusually long. Molecular orbital calculations indicate that this is due to the importance of M-Sn bonding and weak direct M-M interactions. Reaction of 1 with Ph3SnH at reflux in 1,2-dichlorobenzene solvent yielded the complex Rh3(CO)3(SnPh3)3(mu-SnPh2)3(mu3-SnPh)2, 3, which contains eight tin ligands: three terminal SnPh3, three edge-bridging SnPh2, and two triply bridging SnPh ligands.