BIOL 150B Lecture Notes - Doushantuo Formation, Arthropod, Annelid
17 Dec 2013
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Reading: chapter 18, p. 383 (homeotic genes); chapter 21, pp. 457-459 (homeoboxes and hox genes); chapter 25, pp. 32. 2 note the evident polarity in the gastrula stage one end is different from the other. Introduction to animal diversity - 2: almost all animals have hox genes, which contain homeoboxes and which are homeotic in function. Hox genes function during development to specify features of the animal"s body plan. homeobox homeotic gene. Hox genes encode regulators of the transcription of other genes, thereby turning on or off genes whose products build body parts during development. Variation in hox gene activity can therefore lead to variation in animal body plan. A grade is a group of organisms that share an important adaptation, but not through common descent: presence of tissues integrated groups of cells that perform specialized functions. Introduction to animal diversity - 3 no tissues parazoa (sponges, placozoans) tissues eumetazoa.
