front 1 snake venom is an example of | back 1 a complex adaptation |
front 2 complex adaptations are | back 2 phenotypic traits requiring multiple, specific mutations to yield a functional advantage |
front 3 coexpressed traits that experience selection for a | back 3 common, often novel, function |
front 4 DNA can code for | back 4 gene, proteins, and RNA molecules |
front 5 gene control regions | back 5 an upstream section of DNA that includes the promoter region as well as other regulatory sequences that influence the transcription of DNA |
front 6 a promoter is a | back 6 region of DNA upstream of a gene where revelant proteins (such as the RNA polymerase and transcription factors) bind to initiate transcription of that gene |
front 7 gene control regions can also | back 7 bind repressors or transcription factors to regulate the expression of nearby genes |
front 8 a repressor | back 8 is a protein that binds to a sequence of DNA or RNA and inhibits the expression of one of more genes |
front 9 a transcription factor | back 9 is a protein that binds to specific DNA sequences and acts like a light switch by turning all the sequences on or off simultaneously |
front 10 regulatory networks are often | back 10 involved in complex adaptations |
front 11 regulatory network is a | back 11 system of interacting genes, transcription factors, promoters, RNA, an other molecules. It functions like a biological circuit, responding to signals with output that controls the activation of genes, during development, the cell cycle, and the activation of metabolic pathways. |
front 12 hox genes | back 12 a set of transcription factor genes show unusual property, provide a glimpse of one way where gene expression is translated into the many different forms that metazoans (animals) exhibit. |
front 13 hox genes, in contrast, are genes that | back 13 specify segment identify and they are all clustered together in one (usually) tidy spot. Within that cluster, there is even further evidence of order. The genome seems to have various randomly scattered genes, with no order present in the arrangement on a chromosome, the order is only shown in expression thru the process of development. |
front 14 drosophila has | back 14 8 hox genes in a row, and the genes' order within that row shows their order of expression in the fly body. (3' end of DNA strand [denoted lab: labial] is shown in the head, right of the DNA strand [abd-B: abdominal-B] is shown at the end of the fly's abdomen) |
front 15 hierarchical gene organization controls | back 15 development of animal embryos |
front 16 some expressed genes shut down other genes, for example Distallelss (DII), involved | back 16 in the production of antennae and legs, is repressed by homothorax (hth) and so is not expressed in the abdomen of the fly |
front 17 hox genes are expressed | back 17 during development (development genes) |
front 18 knocking out individual Hox genes in Drosophila causes | back 18 homeotic transformations (one body part develops into another) |
front 19 Antennapedia mutant | back 19 lega develop on the fly's head instead of antennae |
front 20 Hox genes enable the | back 20 development of morphologically distinct regions in a segmented animal (activation from the 3' end s the start of a segment to develop into part of the head) |
front 21 mutations to genes at the top of the hierarchy can have | back 21 drastic effects |
front 22 gene duplication can produce | back 22 novel functions |
front 23 promiscuous proteins | back 23 capable of carrying out two functions; likely to take on new functions if duplicated |
front 24 paralog | back 24 homologous gene that arises by gene duplication |
front 25 gene recruitment | back 25 co-option of a particular gene or network for a totally different function as a result of a mutation; reorganization of a preexisting regulatory network can be a major evolutionary event |
front 26 New adaptations in microbes: E.coli long term evolution experiment | back 26 12 initially identical populations of asexual Escherichia coli bacteria, evolved the ability to feed on citrate in the growing medium in the absence of oxygen |
front 27 snake venoms evolved through | back 27 duplication and co-option |
front 28 crotamine genes in snake venome are | back 28 closely related to beta-defensins the bacteria-fighting molecules found in many vertebrates |
front 29 regulatory mutation led to | back 29 production of defensin gene in the mouth |
front 30 venom genes have been recruited from | back 30 genes expressed in many organs in snakes |
front 31 venom evolved before | back 31 snaked evolved |
front 32 directional terminology | back 32 anterior: front posterior: rear dorsal: back ventral: belly proximal: close to center of mass distal: away from the center of mass |
front 33 hox genes are part of a conserved | back 33 "genetic toolkit" among animals (common ancestor passed this gene to flies and mammoths[diverse animals]) |
front 34 dorsal-ventral patterning is conserved; flies and mice use | back 34 homologous genes for dorsal-ventral patterning, though they are expressed as "mirror images" |
front 35 the phylogeny of animals informs as to how | back 35 the genetic toolkit was deployed (dorsal-ventral patterning and single nerve cord in annelids, anthropods, and vertebrates) |
front 36 mouse legs start as a bulge known as a limb bud | back 36 mice build proximal structures then more distal structures |
front 37 fly legs develop as a series of concentric structures | back 37 the "bulls-eye" is the most distal part of the leg |
front 38 ortholog | back 38 is one of two or more homologous genes separated by a speciation event |
front 39 paralogs | back 39 homologous genes produced by gene duplication, that are both possessed by the same species |
front 40 fly and mouse leg genes reflect | back 40 derivation from genes in a common ancestor |
front 41 in flies, Engrailed (En) gene helps | back 41 define the posterior portion of the limb bud in mice. its ortholog in mice has an identical role in the leg disk |
front 42 in flies, engrailed proteins | back 42 turn on the expression of the signaling gene Hedgehog (Hh) |
front 43 combination of signals (high Hh and absence of En) causes | back 43 cells to begin expressing two additional signaling genes Decaptenaplegic (Dpp) and Wingless (Wg), these interact to produce (DII) and (EGFR) affecting the development of limb |
front 44 blocking Shh gene expression | back 44 stops limb patterning pathway |
front 45 fins appear in the | back 45 foosil record 400 mys |
front 46 in fish mesodermal tissues produce | back 46 a cluster of skeletal bones near the base of the fin |
front 47 AER (apical ectodermal ridge) (Hoxa11 and Hoxd13 overlap) | back 47 stimulated distal growth of the limb bones in the mesodermal tissue (when Hox genes ceases, fin rays begin to grow from extodermal ridge tissue) |
front 48 in tetrapods, skeletal bones derived from | back 48 the mesoderm become much longer, forming the long bones of the limb (later the smaller bones develop) |
front 49 in tetrapod limbs, Hox genes become | back 49 active a second time later in development and their domains of expression no longer overlap (evolution of tetrapods limbs involves changes to the timing and location) |
front 50 Hoxd13 in development of a fish fin (create an appendage with a striking resemblance to a tetrapod limb) | back 50 this is a pleiotropic effect, simultaneously shrinking the outer area of the fin where fin rays develop and expanding the region where bone grows |
front 51 expression differences in a single gene give | back 51 rise to limb elongation |
front 52 increased expression of Bmp2 stimulates | back 52 extra growth in the finger bones of bat forelimbs |
front 53 complex eyes have evolved in | back 53 several different lineages |
front 54 each kind eye contains ___ for directing incoming light and ___ opsins for capturing it. But particular molecule for each eye are different. | back 54 crystallins, opsins |
front 55 crystallin | back 55 water-soluble structural protein found in the lens and the cornea of the eye for transparency |
front 56 opsins | back 56 proteins that bind to light-reactive chemicals to underline vision, phototaxis, circadian rhythms, and other light meditates responses of organisms |
front 57 opsins evolved in a | back 57 common ancestor around 1 bya |
front 58 crystallins evolved though | back 58 gene recruitment |
front 59 gene recruitment (or co-option) | back 59 the placement of a new gene under a foreign regulatory system, can lead to increase in genomic complexity, is recognized as major driving force in evolution |
front 60 laws of physics | back 60 atmospheric O2 concentrations constrain insect size |
front 61 antagonistic pleitropy | back 61 single gene affects expression of many traits mutations may have positive effects for one trait but negative effects for another trait |
front 62 antagonistic pleiotropy: number of cervical vertebrae in all mammals | back 62 7 in their necks |
front 63 note the routing of the recurrent laryngeal nerve in the giraffe neck, | back 63 carries the constraint of looping around gill arch blood vessels |
front 64 convergent evolution | back 64 independent evolution leading to similar traits in two different lineages (similar selection pressures) |
front 65 parallel evolution | back 65 independent evolution of similar traits in multiple lineages, all starting from a similar ancestral condition |
front 66 cavefish species exhibit | back 66 parallel evolution in depigmentation |
front 67 deep homology | back 67 growth and development of traits in different lineages result from underlying mechanism inherited from a common ancestor |
front 68 deep homology may help to | back 68 explain cases of parallel evolution |