What Does “ITS” Say about Hybridization in Lineages of <i>Sarsia</i> (Corynidae, Hydrozoa) from the White Sea?

Hydrozoans are widely known for their complex life cycles. The life cycle usually includes an asexual benthic polyp, which produces a sexual zooid (gonophore). Here, we performed an extensive analysis of 183 specimens of the hydrozoan genus Sarsia from the White Sea and identified four types of gonophores. We also compared the type of gonophore with haplotypes of the molecular markers COI and ITS. Analysis of COI sequences recovered that the studied specimens related to the species S. tubulosa, S. princeps and S. lovenii, and that the S. lovenii specimens divided into two COI haplogroups. More intraspecific genetic diversity was revealed in the analysis of the ITS sequences. The Sarsia tubulosa specimens divided into two ITS haplotypes, and presumably, hybrid forms between these lineages were found. For S. lovenii, we identified 14 ITS haplotypes as a result of allele separation. Intra-individual genetic polymorphism of the ITS region was most likely associated with intraspecific crossing between the different haplotypes. The diversity of the morphotypes was associated with the genetic diversity of the specimens. Thus, we demonstrated that the morphologically variable species S. lovenii is represented in the White Sea by a network of intensively hybridizing haplotypes. Hybridization affects the morphology and maturation period of gonophores and presumably affects the processes of speciation

Molecular left-right patterning after formin inhibition.

(A) Scheme of time course of chemical treatment and stages of LR analysis. (B, B’) Formin inhibitor SMIFH2 had no effect on nodal1 expression patterns in the embryos treated during cleavage (N = 3) and reduced the proportion of left-sided nodal1 expression in the embryos treated during gastrulation and neurulation (N = 6, p = 0,00000313 for 10μM SMIFH2). (B) Summary of experimental data. (B’) Representative images of formin-modulated stage 28 tailbud embryos displaying left-sided and abnormal (right, absent and bilateral) expression of nodal1, ventral view. (C, C’) Formin inhibitor SMIFH2 had no effect on pitx2 expression patterns in the embryos treated during cleavage (N = 4) and reduced the proportion of left-sided pitx2 expression in the embryos treated during gastrulation and neurulation (N = 7, p = 0,0005445 for 10μM SMIFH2). (C) Summary of experimental data. (C’) Representative images of formin-modulated stage 28 tailbud embryos displaying left-sided and abnormal (right, absent and bilateral) expression of pitx2, ventral view. A, anterior; L, left; P, posterior; R, right. ***, p-value<0.001 compared with the DMSO control, two-proportions z-test with Bonferroni correction; N, number of experiments. Numbers at the base of columns represent number of analyzed embryos.</p

Representative histological sections through GRP of embryos at stage 18 treated with 10 μM SMIFH2 at stages 10–18, demonstrating position of <i>nodal1</i> and <i>dand5</i> expressing cells.

Arrows indicate areas of superficial nodal1 and dand5-positilklllve cells. (JPG)</p

Formin inhibition at gastrula and neurula stages results in morphology defects of left-right organizer at stage 18.

(A) Representative scanning electron microscopy images of GRP after exposure to various concentrations of formin inhibitor. (B) Representative histological sections through the GRP after exposure to various concentrations of formin inhibitor. Blue color indicates ectoderm, red–notochord and hypochord, violet–somitic mesoderm, yellow–endoderm. (C) Cilia polarization, cilia length and percentage of ciliated cells (ciliation rate) in embryos treated with DMSO and SMIFH2 (5 μM and 10 μM). Measurements were performed in notochordal GRP of 11, 14 and 9 embryos respectively (number of analysed cells = 303, 453 and 234 respectively). The apparent decrease of number of ciliated cells is non-significant (p-value = 0,295 for 10 μM, t-test with Bonferroni correction).</p

Le Peuple : organe quotidien du syndicalisme

09 mai 19331933/05/09 (A13,N4496)-1933/05/09

Formin inhibition at gastrula and neurula stages results in abnormal molecular patterning of GRP.

(A-B’) Representative images of molecular patterning in the GRP. Dorsal explants of stage 18 neurula embryos after control treatment (A,B) and SMIFH2 administration (A’,B’) at stages 10–18. In situ hybridisation was performed with probes specific for sox17 (A,A’) and tekt2 (B,B’). (C and C’) Representative images of nodal1 expression pattern in the GRP. Dorsal explants of stage 18 neurula embryos after control or SMIFH2 treatment at stages 10–18. (D and D’) Histological sections through GRP demonstrate the position of nodal1-positive cells in the prospective somitic mesoderm. Arrows indicate areas of superficial nodal1-positive cells.</p

Visceral organ situs after formin inhibition.

(A) Representative images of formin-modulated stage 46 tadpoles displaying normal organ situs (ss), situs inversion (si), or heterotaxia (ht), as determined by the direction of heart looping (outlined by dashed red line) and gut coiling (outlined by dashed violet line), ventral view. (B) Formin inhibitor SMIFH2 had no effect on organ situs in the tadpoles treated during cleavage (N = 5) and reduced the proportion of tadpoles with normal organ laterality after treatment with 10 μM SMIFH2 during gastrulation and neurulation (N = 5). a, anterior; ht, heterotaxia; l, left; p, posterior; r, right; si, situs inversus; ss, situs solitus. Cyan arrows indicate heart ventricle, yellow arrows indicate truncus arteriosus. ***, p-value = 0,00006552 compared with the DMSO control, two-proportions z-test with Bonferroni correction; N, number of experiments. Numbers at the base of columns represent number of analyzed embryos.</p

Formin inhibition at cleavage stages has no effect on morphology and molecular anatomy of GRP in embryos treated with DMSO and 10 μM SMIFH2.

(A) Representative scanning electron microscopy images of GRP. Dorsal explants of stage 18 neurula embryos after formin inhibition at stages 2–6.5. Red color indicates notochord and hypochord, violet–somitic mesoderm, yellow–endoderm. (B-D) Representative images of molecular patterning in the GRP. Dorsal explants of stage 18 neurula embryos after formin inhibition at stages 2–6.5. In situ hybridisation was performed with probes specific for nodal1 (B), sox17 (C) and tekt2 (D). (JPG)</p

S3 Fig -

Compilation of nodal1 (A) and dand5 (B) expression at stage 18 in embryos treated at gastrula-neurula stages with DMSO and 10 μM SMIFH2. (JPG)</p