According to the results obtained in the laboratory exercise, it appears that the gene to centromere distance tends to vary at different temperatures, as well as with different environmental conditions. At different environmental conditions, variations in recombination frequencies are found in Sordaria . Recombination generates new combinations of existing genetic variation and therefore may be important in adaptation and evolution ( Saleem2001). Throughout the years it has been observe how different species have adapt to different environmental conditions, and because of the new spices have evolve. A variable recombination frequency dependant on environmental conditions can provide to an organism the ability to survive at different temperatures or different environmental conditions.
In addition variable recombination frequencies at different environmental conditions can ensure genetic variation as well. When observing the results from different crosses it can be observe how temperature influences the behavior of the organisms. The results are due to the effects of temperature upon crossing-over and that chiasma interference in conjunction with differences in chromosome structure may account for the three varied patterns of segregation. (Olive 1956).This paper discusses and investigates, whether there was natural genetic variation for recombination frequencies and whether any such variation was environment related and possibly adaptive (Salem2001). In the results obtained from the lab it can be observe, how the numbers in percent crossing over varies between crosses as well as in different environmental conditions. In graphs 1 and 2 it can be observe how the percent of crossing over is higher in the cultures incubated at ...
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...he percent of crossing over at different temperatures, temperature govern chiasma frequency by interference (Olive 1956). One thing can be consider, temperature plays a very important role in crossing over frequency. Finally, temperature affects crossing over by increasing or decreasing the percent of crossing over in each of the Sordaria crosses.
Works Cited
B. C. LAMB, Related and unrelated changes in conversion and recombination frequencies with temparature in Sordaria (1968)
Lindsay S. Olive. Genetics of Sordaria fimicola. I. Ascospore Color Mutants (1956)
Muhammad Saleem ,Bernard C. Lamb ,and Eviatar Nevo, Inherited Differences in Crossing Over and Gene Conversion Frequencies Between Wild Strains of Sordaria fimicola From "Evolution Canyon" (2001)
AGNES M. TOWE AND D. R. STADLER, Effects of temperature on crossing over in Neurospora , (1963)
We placed elodea plants into three different beakers and labelled them. Since, we are trying to find how temperature can affect the rate of production of carbon dioxide, we had to place them in different temperatures. So, we labelled the first beaker “Elodea heat” and placed it in a water bath that produced sufficient amount of heat. We labelled the second one “Elodea cool” which was placed in an ice bath filled with ice. The next one “Elodea RT” where the elodea was placed under normal room temperature without any interference. And we named the last one “No Elodea” where we placed no elodea in it and kept the beaker in a dark
Test 4: All three phenotypic frequencies saw a reduction in their number as the homozygote fishes saw a reduction in their number and were not able to pass on their alleles to create either their colored fish or a heterozygote. Both yellow and blue allele frequencies decreased by the same
The gels were run at 90-100 volts for 1-1.5 hours. Upon completion of the experiment, we were able to examine the DNA. First, the electrophorese. revealed that three of the fourteen samples were homozygous while the other eleven were
For the original analysis, the corrected pairwise distance will be calculated using the Jukes–Cantor and the Maximum Composite Likelihood Model. The Jukes–Cantor model assumes that the rate of nucleotide substitution or all nucleotides (C, A, T and G) are equal, that nucleotide frequencies are equal, that there is an equal rate of substitution among sites, and does not correct for the lower rate of transversion substitutes in comparison to transitional substitutions (Jukes and Cantor, 1969). The Maximum Composite Likelihood takes into account the phylogenic relationship between sequences, using the sum of the log likelihoods of the bases as the composite likelihood. Both pair wise distances and substitution parameters are estimated using the Maximum Composite Likelihood (Tamura et al. 2004). Both models should yield different maximum sequence divergence and average divergence that can then be compared to the original paper. With sequence divergence data, the temporal origin of the genus can be identified. The two alternate models to the Kimura-2 parameter will be analyzed to discuss which methods yield results closest to the expected time origin of the genus
Evidence has shown that the corn we know today is quite different from the first time it was domesticated in Mexico. Although researchers and the academic world acknowledge that corn began its world journey in Mexico, they are unsure as to the time and location of the earliest domestication (American Society of Plant Biologist). Through genetics, teosinte is found to be corn’s wild ancestor. Although the two do not look much alike, at a DNA level they are surprisingly alike, such as having the same number of chromosomes and a remarkably similar arrangement of genes (The University of Utah).
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.
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
Sordaria fimicola is a species of microscopic fungus that is an Ascomycete and are used to test for genetic variation in the lab setting (Sordaria fimicola: A Fungus used in Genetics, Volk). These organisms are what are called model organisms, or species that has been widely studied usually because it is easy to maintain and breed in a laboratory setting and has particular experimental advantages (Sordaria fimicola, Volk). S. fimicola, because it is in the Ascomycota phylum, have a distinguishing reproductive structure called the ascus, which is surrounded by the perithecium. This cylindrical sac-like structure houses 8 haploid spores; created through meiosis to produce 4 haploid spores and then mitosis to make 8 (Lab Manual, pg. 59-68). Based on the genotype they will vary in order and color. There are 3 different ratios that can arise from the 8 ascospores: 4:4, 2:2:2:2, and 2:4:2 (black/wild type and tan coloration). The 4:4 ratio suggests that no crossing over had occurred because there is no difference in order of the color parents that were mated. The two other ratios suggest genetic recombination, or crossing over, because of the
16. Describe two evolutionary consequences if the process of crossing over in meiosis ceased to occur. If crossing over in meiosis ceased to occur there would be less genetic variations and no diversity among a species. This would essentially mean that a species would not be able to adapt to an issue that could arise in the future, meaning that its species could potentially become extinct due to climate change or other arising events.
Rantala, M. J., and Roff, D. A. 2006. Analysis of the importance of genotypic variation,
In order to figure out the genes responsible, there are several other factors that must be determined. These factors include the number of genes involved, if each gene is x-linked or autosomal, if the mutant or wild-type allele for each is dominant, and if genes are linked or on different chromosomes. Proposed crosses include reciprocal crosses between the pure-breeding mutants of strains A and B with the wild-type will help determine if the genes or sex-linked or autosomal, in addition to which alleles are dominant (8). Another proposed cross includes complementation crosses between pure-breading mutants from strains A and B to determine if one or two genes are involved (8). Furthermore, testcrosses between F1 progeny and pure-breeding recessive mutants from strains A and B, which will help determine if genes are linked on the chromosome or if they assort independently (8). These proposed crosses are shown in the attached
Abstract: This paper analyzes whether or not gene mapping in Sordaria fimicola is affected by changes in environmental conditions. The main focus is on how temperature affects the recombination frequency of this organism. It is analyzed if under different environmental conditions wt x gray and wt x tan varies in their percentage crossing over. It is investigated how factors such as temperature and ultraviolet light have affected the gene to centromere distance in Sordaria.
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.
As previously stated, there are several ways that these changes can occur, but the ones I will be focusing on are changes occurring to methyl and acetyl groups. The mechanism of heritability in animals is information coded into genes. Genes are wrapped around histones in the nucleus. When methyl groups attach to these histones, it winds the genes tighter, and since the shape is altered, it also alters the protein the gene codes for. Generally speaking, when you add a methyl group onto the histones, or "spool" of the gene, it makes it harder to code that gene’s proteins, just like if you got something stuck in the chain on your bike and tried to pedal it. The more methyl groups that build up, the worse the problem becomes. However, in most of the cases acetylation unwinds some of the histones, activating or reactivating a gene. Scientists are explo...
M Dufrasne, I. M. (2013). Journal of Animal Science. Animal Genetics , Volume 91 (12).