Robert Warren, Lisa Nagy, Jane Selegue, Julie Gates, and Sean Carroll produced this experiment that wanted to examine homeotic gene expression in butterflies. The hypothesis they tested was do homeotic genes have driven morphological change or do the homeotic genes provide a pre-existing plan where insects segment diversity evolved. The genes Antp, Scr, Abd-A, and Ubx were isolated from a cDNA library and were used to explore differences in limb and wing numbers between flies and butterflies. Where Ubx and Abd-A are expressed, the limb and wing numbers arose. They started to wonder if the expression of BX-C genes were different in butterflies (P.Coeni) and fruit flies (drosophila). When they did tests, they saw that conservation of BX-C and ANT-C homeotic gene expression are fundamentally similar and don’t explain the differences in appendages in each species. They looked into embryogenesis, and at 20% of the embryogenesis of butterflies, they saw Abd-A protein and RNA are expressed in the anterior and abdominal segments. High levels of Antp expression are seen in the thorax. Past the 20% mark of embryogenesis, the patterns seen of Abd-A, DII, and Antp expression differed extremely - no DII or Antp were expressed in the abdominal proleg.
After seeing this, they tested out if DII is responsible for the down regulation of Ubx/Abd-A. They used double-label experiments using antibodies against butterfly DII and Ubx/Abd-A antibodies and performed them. The activation of DII in the proleg trails repression for Ubx and Abd-A expression, which showed that repression of BX-C gene, is the initial event. When DII expression abdominal segments of drosophila embryo expression is repressed due Ubx and Abd-A, the abdominal limb formation in but...
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...nes to produce different kinds of structures patterned in the same position. In general, 0 changes the number, size, pattern of homologous structure, and body appendages, that involve changes in timing and spatial regulation of existing genes. In some cases, these are homeotic genes and in other cases they are downstream genes.
If I were to continue this line of research, I would test and see if there are different hox genes for different animals. I would expect to see duplication to occur in the lineages within each species. For example, if duplication were to occur at hox gene levels (in butterflies, fruit flies, earthworms, etcetera) I would expect to see different hox genes. But, since hox how genes are conserved, that would probably not end up happening. So this new test would prove that hox genes are conserved and every species should have the same hox genes.
University of South Florida. 2017. Phylogeny, Evolution, and Population Genetics in Drosophila melanogaster. Biodiversity Lab
There is no doubt that arthropods are an extremely successful group of animals, with an estimated 5-10 million species worldwide[1], and this can be attributed to having an exoskeleton; it provides many benefits, such as protection from parasitism and other threats. However, one major disadvantage of having an exoskeleton is the limitations that an inelastic cuticle can place on growth. The exoskeleton provides protection, but when freshly moulted the animal is soft and vulnerable, as well as having limited mobility and use of appendages; many seek shelter before moulting[2]. There are similarities and differences between the moult cycles of all the arthropods, however only crustaceans and insects will be discussed here.
Conclusion for class di-hybrid cross: The p value 0.779 is in the non-significant range in the chi square table. The null hypothesis is therefore correct. Sepia eyes and vestigial wings in the flies is a mutation in the genes that is not linked meaning it is a product of independent assortment.
The purpose of this laboratory activity is to investigate the Hardy-Weinberg Law of Equilibrium using the fruit fly Drosophila melanogaster. According to the Hardy-Weinberg Law of equilibrium, allele frequencies should remain the same in large populations that do not experience gene flow, mutations, nonrandom mating, and natural or artificial selection. We will be studying the alleles that determine wing shape, either normal (wild type) wings or vestigial wings. Vestigial females will be crossed with equal numbers of vestigial males and wild type males. I this population is at Hardy-Weinberg equilibrium we would predict an equal number of wild type and vestigial offspring in the next generation.
The purpose of the first experiment, Ebony vs. Vestigle was to see how many of the offspring had normal bodies and normal wings, normal bodies and vestigle wings, ebony bodies and normal wings, and ebony body and vestigle wings. The purpose of the second experiment White vs. Wild was to see how many of the offspring were red eyed male, white eyed male, red eyed female, and white e...
Long standing arguments against the theory of natural selection stem from the occurrence of incipient structures and complex traits in organisms despite the seemingly stochastic nature of mutations. Many complex adaptations observed in nature today are thought to have arisen from less complex ones with simpler functions, therefore these characters are thought to have been “pre-adapted.” In order to go from a simple to a complex structures there must have been a transitional phase, where the two structures function simultaneously or where the new function is assumed without interfering with the old function. These structures are termed incipient or incomplete, and given what we know to be true of natural selection and the theory of evolution it becomes hard to reconcile the idea that natural selection continued to favor these structures despite the lack of selective value. Incipient structures are thought to be neither sufficiently large enough not elaborate enough to perform an adaptive function and thus it also becomes difficult to understand how larger complex characters arise. A discussion of morphological and developmental genetics explains that these structures have been performing useful functions since their simple origins, therefore being selectively favored while at the same time evolving to become large enough to accumulate new more complex functions. Modification of pre-existing genes and regulatory circuits in early development has been extensively studied in metazoans, Hox genes and the development of complex structures such as eyes, limbs and appendages. Phenotypic variation is therefore generated via the modification of existing genes, regulatory processes and developmental processes and this variation is acted o...
In Drosophila, there are eight hox genes, which are generally divided up into two complexes, the antennapedia and bithorax. The antennapedia complex contains genes responsible for coding for the head and thorax regions of the body and begins at the 3’ end of the DNA sequence making up the homeotic gene cluster. On the other hand, the bithorax complex codes for the abdominal region of the body and is located at the 5’ end of the DNA sequence. While the pair-rule and segment polarity genes are the ones that establish the segments along the body of the fly embryo, it is the homeotic genes that then assist in determining the identities of each specific segment. This ultimately leads to a distinct anterior-posterior polarity along the ...
This means putting all the flies to sleep by fly nap and taking them out to observe traits. Observe the traits under a microscope because the flies are so small. Separate the flies by sex and phenotypes. Record the data collected in the table of your lab manual. Experiment one can now perform a new cross with the F1 x F1 with five males and females from the fly house and place them in a new fly house. The testcross is established by wild type females that are heterozygous and dumpy/ sepia males that are homozygous. Lay both houses on its side and clearly label. Experiment two can now perform a F1 xF1 cross with five females and five males from the old fly house into a new fly house. The testcross for experiment two is wild type female’s heterozygous and sepia/ebony males homozygous from the parental generation into a new fly
3 Leicht B. G., McAllister B.F. 2014. Foundations of Biology 1411, 2nd edition. Southlake, TX: Fountainhead Press. Pp 137, 163-168, 177-180,
Davis, Lloyd S. and John T Darby. Penguin Biology. San Diego: Academic Press, Inc., 1990.
The F2 punnett square shows that there should not be a female fly that has apterous wing mutation. Our observed experiment showed that female flies are capable of forming in the F2 Generation. Therefore, the mutation is located on autosomal chromosomes. In trial 1, the p value is not significant. This could be due to the fact that the male to female ratio in the F1 generation was unequal. In trial 2, the p value is significant and likely due to chance. The probability error is between 1 % and 5%.
A lot of butterflies have developed eye spots on their wings. These eye spots provide the butterfly the facade of a much bi...
Distinct characteristics are not only an end result of the DNA sequence but also of the cell’s internal system of expression orchestrated by different proteins and RNAs present at a given time. DNA encodes for many possible characteristics, but different types of RNA aided by specialized proteins sometimes with external signals express the needed genes. Control of gene expression is of vital importance for an eukaryote’s survival such as the ability of switching genes on/off in accordance with the changes in the environment (Campbell and Reece, 2008). Of a cell’s entire genome, only 15% will be expressed, and in multicellular organisms the genes active will vary according to their specialization. (Fletcher, Ivor & Winter, 2007).
Evolutionary developmental biology (evo-devo) was instituted in the early 1980s as a distinctive field of study to characterise the new synthesis of evolution hypothesis (Müller, 2007). Evo-devo is regarded as a new rule in evolutionary biology and a complement to neo-Darwinian theories. It has formed from the combination of molecular developmental biology and evolutionary molecular genetics; their integration has helped greatly to understand both of these fields. Evo-devo as a discipline has been exploring the role of the process of individual development and the changes in evolutionary phenotype, meaning the developmental procedure by which single-celled zygotes grow to be multicellular organisms. Alterations in the developmental program frequently cause differences in adult morphology. When these alterations are helpful, they grow to be fixed in a population and can result in the evolution of new phyla. Evo-devo seeks to figure out how new groups happen by understanding how the method of development has evolved in different lineages. In other word, evo-devo explains the interaction between phenotype and genotype (Hall, 2007). Explanation of morphological novelty of evolutionary origins is one of the middle challenges in current evolutionary biology, and is intertwined with energetic discussion regarding how to connect developmental biology to standard perspectives from the theory of evolution (Laubichler, 2010). A large amount of theoretical and experiential effort is being devoted to novelties that have challenged biologists for more than one hundred years, for instance, the basis of fins in fish, the fin-to-limb change and the evolution of feathers. The biology of development promises to formulate a main contribution to these...
During prophase I, homologous chromosomes pair and form snynapses. The paired chromosomes are called bivalents, and the formation of chiasmata caused by genetic recombination becomes apparent. The bivalent has two chromosomes and four chromatids, with one chromosome coming from each parent.