Introduction
“All animals exhibit innate behaviors that are specified during their development.” Drosophila melanogaster (fruit fly) males exhibit complex sexual courting behaviors towards females; these sexual behaviors are only directed from males towards females and are not present in females. The fruitless (fru) gene, which is spliced differently in males and females, has been shown to perhaps have something to do with this male-fruit-fly-attributed innate courtship ritual. This research paper seeks to determine whether this fru gene is a “switch” gene that is “necessary and sufficient to specify male courtship behavior and sexual orientation.” Gene targeting was used to splice the fru gene and exchange it between male and female fruit flies to determine differences in courtship behavior that could be attributed to the loss or gain of the fru gene. From this experiment, insight into the importance of this gene in male courtship behavior can be attained.
Results
Fru regulates sexual behavior but not gross sexual anatomy
One of the conclusions which were reached by the researchers was that fru regulates sexual behavior, not the gross anatomy of the drosophila. In drosophila, the sex determination hierarchy separates into two parts. Like in fru, the doublesex gene (dsx) is spliced differently and it produces dsxM or dsxF. These dsx proteins do not have to do with the sexual behavior of drosophila, but rather they have to do more with their morphological development. This became evident because when there is a male drosophila which does not have dsxM he still courts but possesses female anatomy, and vice versa. This brought the researchers to the conclusion that the dsx indeed does not have to do with...
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...established recently through exact gene manipulations. FruM has four unique aspects that stand out in order to determine other switch genes. First, it acts during the development of the individual and creates a potential for a behavior and does not influence the behavior directly. Second, to our current knowledge it is involved in most aspects of the behavior. Third, “loss-of-function mutations do not result in a general impairment of neural function, but a specific behavioral deficit.” Fourth, it is required to affect the role in the gene.
References
Demir, E., and Dickson, B. J. (2005). Fruitless Splicing Specifies Male Courtship Behavior in Drosophila. Cell 121; 785-794.
"Glossary." Geron. 2004. 1 Dec. 2006 showpage.asp?code=prodgl>. Purves et al. Life: The Science of Biology. Seventh Ed. Sinauer Associates, Inc., 2004.
Examining the Crosses Between Drosophila Fruit Flies Introduction The major topic of this experiment was to examine two different crosses between Drosophila fruit flies and to determine how many flies of each phenotype were produced. Phenotype refers to an individual’s appearance, where as genotype refers to an individual’s genes. The basic law of genetics that was examined in this lab was formulated by a man often times called the “father of genetics,” Gregor Mendel. He determined that individuals have two alternate forms of a gene, referred to as two alleles.
The purpose of this experiment is to conduct genetics studies using drosophila fly as the test organism. Scientists can study the basic biology that is shared by all organisms using a model organism, such as drosophila fly1. Drosophila fly, or more commonly known as fruit fly, has several qualities that makes it well suited for experimental genetics cross. First, fruit flies are low maintenance organisms. They are small in size (few millimeters long), so they occupy a small space and a lot of them can fit in one vial at the same time. They only require a media to feed on. In this lab, instant media was used, which is efficient as it only requires the addition of water to be used. This media contains ingredients that the fruit fly can feed one,
-Reilly Philip. Is It In Your Genes. Cold Spring Harbor Laboratory Press. 2004: 223-228. Print
Every species has their unique way to survive and interact with their environment. Some have extra appendages in order to better combat predators, or they have bodies that allow them to camouflage to their environment. Every species also has their way of reproducing and copulation, whether for necessity or for enjoyment. Two species with different mating habits are the Apis mellifera, better known as honey bees, and Pan paniscus, Bonobos apes. The former uses its reproduction methods for the survival of the entire colony of honey bees in exchange with the death of few and the former uses copulation in a social setting in order to keep the peace of the pack.
"Persistent female choice for a particular male trait values should erode genitive variance in male traits and thereby remove the benefits of choice, yet choice persists” (Miller, Christine and Allen Moore). This phenomenon is know as the Lek Paradox and has puzzled scientists for many years. Throughout all species there has been abundant evidence showing continuous female choice of male traits, yet there is still no definite answer as to what allows for genetic variance to be maintained, and why a specific trait never becomes fixed. Many hypotheses have been theorized and researched, all providing some explanation as to how this variance in species is maintained, from traits signaling resistance to parasites, according to Hamilton and Zuk, to the hypothesis of mutational and environmental affects. Condition-dependence can also provide information as to how the lek paradox is able to exist; this hypothesis will be looked at in this paper.
Some individuals have developed different traits to help them in the process of intra-sexual competition. The organisms with more distinctive traits have greater reproductive success. More genes of those traits are then ‘selected’ and are passed onto the offspring of the organisms. Throughout time variability in these traits becomes
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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%.
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Evolutionary framework for human mating is based on three elements. First, strategies for mating developed to solve specific problems in human evolutionary history. Second, people behave differently depending on the type of mating involved. There are two types of mating, short term and long term mating. Short term mating is defined as casual sex (i.e. one-night stands and brief affairs). Long term mating is seen as a committed relationship (i.e. dating, going steady, and marriage). Third, males and females developed different strategies due to the difference in problems they have had over the course of human evolution (Buss 241). This paper will examine those strategies specific to males.
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