To test whether the known connectivies of neurons in the lamprey spinal cord are sufficient to account for locomotor rhythmogenesis, a CCconnectionist" neural network simulation was done using identical cells connected according to experimentally established patterns. It was demonstrated that the network oscillates in a stable manner with the same phase relationships among the neurons as observ...

Different species maintain a particular body orientation in space due to activity of the closed-loop postural control system. In this review we discuss the role of neurons of descending pathways in operation of this system as revealed in animal models of differing complexity: lower vertebrate (lamprey) and higher vertebrates (rabbit and cat). In the lamprey and quadruped mammals, the role of sp...

We carry out fluid-structure interaction simulations of self-propelled virtual swimmers to investigate the effects of body shape (form) and kinematics on the hydrodynamics of undulatory swimming. To separate the effects of form and kinematics, we employ four different virtual swimmers: a carangiform swimmer (i.e. a mackerel swimming like mackerel do in nature); an anguilliform swimmer (i.e. a l...

Electrophoretic expression of 20 enzymes coded by a minimum of 30 gene loci is reported for sea lamprey. ADA, ADH. AGP, AAT, CPK, G6PDH, GAPDH, LDH. MDH, PEP, 6PCD, PGI, PGK, PGM, PK, PMI, and SDH yielded gel resolution satisfactory for use in future population studies. Six loci, AGP, !LZDH-1, PGI-I, PGI-2, PGi%f-l, and PlMI were polymorphic. Enzyme expresion did not vary between life stages (a...

The complete mitochondrial genomes were sequenced in anadromous and resident forms of the lamprey Lethenteron camtschaticum. The sizes of the genomes in the two isolates are 16,245 and 16,295 bp. The gene arrangement, base composition, and size of the two sequenced genomes are similar to the lamprey genomes previously published. The total sequence divergence between the two genomes is very low ...

Evolutionary conservation of hindbrain segmentation in vertebrates. On pages 526–538 of this issue, Parker et al. explore the origin and diversifi cation of the Hox gene regulatory network for vertebrate hindbrain segmentation and patterning. The cover depicts transgenic embryos of three different species – sea lamprey, mouse and zebrafi sh – expressing fl uorescent proteins in the developing h...

Lampreys, one of the remaining two living jawless vertebrates, carry great weight in study vertebrate evolution. They have a long history dating back to Devonian but left scarce fossil record. So far, only five unequivocal lampreys been described, which four are Paleozoic. Mesomyzon Chang, Zhang & Miao, 2006, known Mesozoic lamprey bridging Paleozoic and extant relatives, was originally conside...

Sea lamprey (Petromyzon marinus) is a species of conservation concern in their native range the Atlantic coasts Europe (Near Threatened to Critically Endangered) and North America (Secure Imperiled), an invasive great economic ecological Laurentian Great Lakes. Despite differences life history strategy (anadromous natives vs adfluvial non-natives), biology sea sufficiently similar expect compar...