The mechanisms responsible for the origin and maintenance of large non-recombining regions on sex chromosomes have been mostly studied in plants and animals, but the recent discovery of similar features on the fungal chromosomes carrying mating type genes in several species may shed new light on this phenomenon (Fraser et al. 2004). Sex chromosomes in plants and animals have evolved from an autosomal pair by the expansion of the non-recombining region around complementary genes determining sex-specific functions (Bergero and Charlesworth 2009). Such a multi-step expansion of the non-recombining regions in sex chromosomes, forming “evolutionary strata” (Lahn and Page 1999), is usually explained by the recruitment of genes determining sexually antagonistic traits (i.e. beneficial in males and deleterious in females, or conversely), via a selection for linkage to the sex-determining genes (Rice 1987, Charlesworth 2005). Selective forces driving the evolution of non-recombining regions are however likely to be different in fungi as cells of different mating types exhibit little phenotypic differences.
In heterothallic fungi, syngamy can only occur between haploid cells carrying different alleles at the mating type genes, while in homothallic fungi, no such differences are required, allowing universal compatibility (Billiard et al. 2011). The two main fungal phyla have different mating type genes and organization: a single locus controls mating type in ascomycetes against two loci in basidiomycetes (i.e. haploid cells should carry different alleles at both loci for successful mating). One of the two loci controlling mating types in basidiomycetes encodes pheromones and pheromone receptors involved in syngamy while the other locus...
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...Smith et al. 2004) and Cryptococcus neoformans (Wang et al. 2002). In R. toluroides, the gene encoding ste20 is surrounded with genes encoding pheromones (Coelho et al. 2008). Other genes, such as the abc1, with more elusive role in mating and development of fungi have also been found in close proximity to the genes encoding the pheromone and its receptor in R. toluroides (Coelho et al. 2008).
In this study, our goals were therefore to: 1) identify additional genes belonging to the mating type locus in Microbotryum, in particular the genes encoding the pheromones and the homeodomain proteins, all of which control mating types in most basidiomycetes, 2) assess whether the genealogies of genes in the mating type region as well as of loci of the previously proposed strata are consistent with the existence of evolutionary strata along the mating type chromosomes.
3 Leicht B. G., McAllister B.F. 2014. Foundations of Biology 1411, 2nd edition. Southlake, TX: Fountainhead Press. Pp 137, 163-168, 177-180,
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
INTRODUCTION: It is often thought that bacteria are usually found on the surface and orifices of organisms. However, one particular genus of bacteria does not conform to this premise, Wolbachia. Wolbachia is a bacterium found within the cells of arthropods. In addition, it is estimated that Wolbachia is found in approximately 66% of all insects (Hilenboecker, 2008). Several studies have been conducted and indicate that the vast majority of arthropods are affected during the reproduction phases. One such study indicates during cell division, Wolbachia isolates itself around spindle poles, and may become incorporated into newly formed daughter cells (Hiroyuki, 1995) In order for Wolbachia to spread within a population, several factors may occur, such as male killings, feminization, and cytoplasmic incompatibility(Toon Ruang, 2004) . In this study, Photinus Pyralis is tested to determine if Wolbachia is present in the genes of these fireflies. Photinus Pyralis, commonly known as a firefly, attract one another through specific flashing signals. These light signals are in the reproductive regions of Photinus pyralis, which is a common infection site for Wolbachia to settle
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%.
Colgan, Wes III, Ramsey, Linda, White, James D., and Spaulding, Jim. Explorations in Biology. 6th ed. Boston: Pearson, 2010. 33-36. Print.
The idea of the project was to experiment breeding Drosophila Melanogaster (fruit fly) to figure out if certain genes of that species were sex linked or not (autosomal). A mono-hybrid cross and di-hybrid cross was performed. For the mono-hybrid cross, white eyed female and red eyed male were placed in one vial for them to reproduce. For the di-hybrid cross, red eyed and normal winged flies and sepia eyed and vestigial winged flies were placed in their vial to reproduce. In the mono-hybrid cross the results expected were within a 1:1:1:1 ratio. Expected results similar to the expected desired null hypothesis proposed with what the F1 parental generation breeds. The potential results would have had to have been within the ratios of 9:3:3:1. The results were clear and allowed the null hypothesis to be correct. The white eyed gene in the fruit flies is sex linked. Sepia eyes and vestigial wings are not sex linked and are examples of independent assortment.
The battle between sexual and asexual reproduction is a competition that has been ongoing for millions of years. Somewhere along the way due to its higher level of genetic variation, sexual reproduction was able to overcome the two fold advantage of asexual reproduction, and now dominates reproduction in organisms. However, some types of organisms such as worms and corals have acquired the ability to reproduce both sexually and asexually. The purpose of this paper is to explore the differences in asexual and sexual reproduction both from a biological and an evolutionary standpoint and to explain why evolution has made it possible for soft corals to reproduce both sexually and asexually.
A Karyotype is when you cut out individual chromosomes from a picture and rearrange them. There are matching pairs of chromosomes these are called homologous pairs. Each pair is given a number. One of each pair came from the mother and one of each pair came from the father. The pairs can be distinguished as each pair has a distinctive banding pattern when stained. There are two sex chromosomes and the rest are called autosomes. In most karyotype the sex cells are kept to one side so that the sex can be seen easily. In females they have two X chromosomes and in the males they have an X and a Y chromosome. The Y chromosome has a portion missing and is therefore smaller then the X chromosome.
Sex and Gender Arianna Stassinopoulos wrote in the 1973 book The Female Woman: "It would be futile to attempt to fit women into a masculine pattern of attitudes, skills and abilities and disastrous to force them to suppress their specifically female characteristics and abilities by keeping up the pretense that there are no differences between the sexes" (Microsoft Bookshelf). In her statement, we see a cultural feminist response to the dominant liberal feminism of the 1970s. Liberal feminism de-emphasized gender differences, claiming that women were the equals of men and that this would be obvious if only they were offered the same opportunities as men with no special privileges necessary. On the other hand, cultural feminists such as Stassinopoulos claimed that women's unique perspective and talents must be valued, intentionally emphasizing the differences between men and women. A third type of feminism, post-modernism, is represented in Sexing the Body by Anne Fausto-Sterling.
Goodrich-Blair, Heidi and Clarke, David J. (2007) Mutualism and pathogenesis in Xenorhabdus and Photorhabdus: two roads to the same destination. Molecular Microbiology 64 (2): 264-268
Luce Irigaray, ’ article, “This Sex Which is Not one,” can be succinctly summarized by the following key points. First, the author mentions the way women are seen in the western philosophical discourse and in psychoanalytic theory. She also talks about the women’s sexuality in many ways. ”Female sexuality has always been concepualtized on the basis of masculine parameters.” Women are seen in qualitatively rather than quantitatively. “Must this multiplicity of female desire and female language be understood as shards, scattered remnants of a violated sexuality? A sexually denied?” Freud mentions that the clitoris is a small penis. The female parts are always seen as a commodity for men. Women don’t need men’s object to pleasure themselves
There is a difference between sex, sex category and gender. Sex is the assigned title at birth based on genitally. West and Zimmerman (1987:127) define sex as “…a determination made through the application of socially agreed upon biological criteria for classifying persons as females or males. The criteria for classification can be genitalia at birth…” Sex categories are the categories (male, female) people are placed into on the basis of their genitally. West and Zimmerman (1987:127) elaborate on this definition, “Placement in a sex category is achieved through application of the sex criteria, but in everyday life.” Sex and sex category can be independent
Campbell, N. A. & J. B. Reece, 8th eds. (2008). Biology. San Francisco: Pearson Benjamin Cummings.
making them less prone to attack by fungi and insects. The use of sex pheromones
In order to answer the question above this essay will discuss in depth what exactly sex is and what gender is and the differences between the two terms. The research carried out will display that we live in a patriarchal society without a doubt as we look at how gender links to inequality in society. A patriarchal society can be clearly seen from the gender inequality in the labour force which is paid labour and also in unpaid labour which occurs in the household. Another area the answer will reflect on is how gender inequality links to education which overall links to society. Finally the answer below will show how the media also portrays gender inequality and how it affects the people in society.