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Shigeru Kuratani PhD 《Theorie in den Biowissenschaften》2003,122(2-3):230-251
Summary The question of vertebrate head segmentation has become one of the central issues in Evolutionary Developmental Biology. Beginning
as a theory based in comparative anatomy, a segmental theory of the head has been adopted and further developed by comparative
embryologists. With the use of molecular and cellular biology, and in particular analyses of the Hox gene complex, the question has been addressed at new levels, but it remains unresolved. In this review, vertebrate head segmentation
is reevaluated, by introducing findings from experimental embryology and evolutionary biology. Developmental biology has shown
that pattern is generated through hierarchically organized and causally linked series of events. The question of head segmentation
can be viewed as a question of generative constraint, that is whether segmentation in the head is imposed by underlying segmental
patterns, as it is in the trunk. In this respect, amphioxus appears to be segmented along the entire anteroposterior axis,
with myotomes and peripheral nerves repeating with the same rhythm (somitomerism). Similarly, in the vertebrate trunk, the
segmental patterns shared by myotomes, peripheral nerves and vertebrae are derived from the somites. However, in the head
of vertebrates there is no such mesodermal pattern, although neuromerism and branchiomerism do indicate the presence of constraints
derived from rhombomeres and pharyngeal pouches, respectively. These data fit better the concept of dual metamerism of the
vertebrate body proposed by Romer (1972), than the traditional head cavity-based segmental model by Goodrich (1930). 相似文献
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Intra‐individual metameric variation expressed at the enamel‐dentine junction of lower post‐canine dentition of South African fossil hominins and modern humans
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Roksana Wilson Christopher E. C. Cooper Rochelle J. Meah Andrew Wakefield Nicholas W. Roberts Gareth Jones 《Ecology and evolution》2023,13(1):e9714
Insect attraction to artificial light can potentially facilitate disease transmission by increasing contact between humans and vectors. Previous research has identified specific wavelength bands, such as yellow and red, that are unattractive to biting flies. However, narrow-band, non-white lights are unsuitable for home lighting use as their very poor color rendering is often considered aesthetically undesirable. The creation of a white light that is unattractive to insects has so far remained elusive. White light can be created by combining a number of narrow-band light-emitting diodes (LEDs). Through choice chamber experiments on Culex pipiens (Cx. pipiens) mosquitoes, we examine whether combining specific wavelength bands has an additive, subtractive or synergistic effect on insect attraction. We show that a white light created by combining narrow-band red, green and blue (RGB) LEDs is less attractive to Cx. pipiens than a broad-spectrum white light; and that a white light created by combining narrow-band blue and yellow LEDs is more attractive than a broad-spectrum white light. White light produced by RGB combinations could therefore serve as a safer and cheaper light in countries where phototactic vectors and vector-borne disease are endemic. 相似文献
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