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ETD 40 A. What are sordaria and how can you use them to figure out map units? B. Why would you want to do this? C. Define each in your own words: Homozygous, Heterozygous, Genotype, Phenotype
January 16, 2014 at 7:56am


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Sophie Wulfing
January 16, 2014 at 10:13pm

Sordaria is a fungus.  Spores are haploids - undergo meiosis then mitosis.  In the process of meiosis brown and black "things" will either be four brown then four black or will be out of order.  If out of order then cross-over occured during meiosis.  More crossing-over means greater distance of the two genes on the chromosome.  Formula for map units % equals 100* (# of cross-over asci / (total # of asci / 2)).  divide by two because they're copies.

C.  Homozygous - 2 of the same alleles; Heterozygous - different hybrid allels; Genotype - which 2 alleles an organism has; Phenotype - which trait is expressed


I had to look up the name of the ascus, and the process of reproduction of the spores, which is a zygote forming, undergoing mitosis to create 4 asci, and them undergoing meiosis and then mitosis to have an eight- asci sordaria. I also need to review the equation for the percentage of crossing over. The final division by two in the equation is derived from the fact that half of the cells are just coppied during mitosis, and didn't actually cross over.

Kevin Turek
January 25, 2014 at 9:32am

Parent: I learned that Sordaria are fungi. They have spores that undergo meiosis and mitosis. This fungus is helpful because it is easy to tell really quick if there is crossing over or not. If the pattern of black and white is not 4 and 4 then you know that there was crossing over. I also learned that you can calculate the percent of crossing over by counting the amount of crossed over asci, then dividing this by the total asci, then multiply this by 100 then divide by 2. Then I also learned that Heterozygous means different combo of alleles. Homozygous means same combo of alleles, Kevin said this is like a purebred dog. Then a genotype is the genetic code for a trait while a phenotype is  a trait being displayed.  

Student: This one was quite difficult to explain. The vocabulary was all new to my mom. She had never heard of sordaria. Also genotype and phenotype were knew to her. I had to look back in my ETD to recall what sordaria were myself.  But I had remembered the formula. Then  heterozygous and homozygous was easy enough because I just said its just like a purebred dog vs a mutt. Then genotype and phenotype was harder because their similar. I said its like having a password genotype and then your account is like the phenotype.


Selena Clem
January 27, 2014 at 9:14pm

Parent: Sordaria are fungi, and their spores can be used to figure out map units by adding the number of spores crossing over, dividing by the total number or spores, and then multiplying by 100. The result will give the distance between two linked genes or the distance from a gene to the centromere in map units.  Homozygous means having 2 of the same allele for a gene (AA or aa). Heterozygous is having 2 different alleles for a gene (Aa). The genotype is the genetic code and the phenotype is the physical appearance that the genotype codes for, such as having blue or brown eyes.

Student: Sordaria spores are normally haploids and form into a diploid zygote in the Ascus (sac) of the fungi, the visible pattern of the colored spores (black vs. tan) shows how many are crossing over (2:2:2:2 or 2:4:2 ratio) which can be added up and divided by the total number of spores and multiplied by 100 to find the percent recombinant frequency which is also the number of map units the two traits, tan and black, are apart from each other. Homozygous=same allele (TT or tt), Heterozygous=different alleles (Tt), genotype= code (Tt), phenotype=physcial appearance of code (tall vs. short)

Madison Boggan
January 06, 2015 at 5:56pm

Parent: Sordaria are a fungus that can help determine map units. This can be done by visually seeing how much cross over occurred and using a formula to determine the map units. Map units are useful as they allow us to determine the location of genes on a chromosome.

Homozygous = same alleles / Heterozygous = different alleles

Genotype = genetic code / Phenotype = what something looks like

Student: After talking to my mom about sordaria and how it helps determine the location of specific genes, we wonder how this has specifically helped with genetic testing and treatment and if there are other ways of determining gene location.

Making or explaining analogies in regards to the vocab helped my brain too. For example, phen in phenotype sounds like seen and phenotype is what can be seen.

Lara Grether
January 15, 2015 at 8:45pm

Parent: This was a very interesting discussion. I learned about the difference between mitosis and meiosis, as well as the definitions of homozygous, heterozygous, genotype and phenotype. Of particular interest to me was learning about how the chromosomes of the Sordaria fungi could cross over and produced unique phenotypes. I also appreciated learning about how the closer the gene is to the end of the chromosome, the easier it is for crossover of that gene to occur. Lara is such an excellent teacher.

Lara: It was really fun talking to my dad. He caught on really quickly to the big ideas of mitosis and meiosis and when I explained the Sordaria and how and why we figure out map units, he was able to repeat the process back to me easily. It also allowed me to revisit crossing over. It was really good for me to review this, and my dad stumped me with a few of his questions that made me backtrack my own thinking in order to make sure what I was saying was correct. It was also good reviewing the terms heterozygous, homozygous, genotype and phenotype in preparation for the upcoming test as it made me reflect on all the punking with punnets we've done. Oh those silly wabbits.

Chloe Hobson
January 25, 2015 at 7:05pm

Student: I explained how sordaria work to determine map units, which tell us how far away a gene is. I explained that the more crossing over there is, the further from the center of a chromosome the gene is. My dad seemed to understand the concept fairly easily, and it was helpful to my understanding of the idea. I taught him about the terms homozygous, heterozygous, and phenotype. This helped me prepare for the test and  was a good review of the main ideas of the chapter. 

Parent: Chloe had a strong understanding of map units and what they are used for. She taught me about how sordaria (a fungus) and map units allow scientists to locate where genes are on chromosomes. She also explained the terms heterozygous and homozygous, breaking down the word parts to teach me. When explaining phenotype, she used the words "phorm" and "phunction" to help explain that the phenotype is the expression of genotype and is what an organism looks like. 

Darci Kudrna
January 12, 2016 at 6:35pm

Parent: Darci attempted to teach me about sordaria which is a fungus.  Sordaria spend most of their lives as haploids.  Then two haploids combine into a diploid.  The diploid is then surrounded by a sack called a ascus which changes them from a side by side diploid into a vertical sequence of a diploid.  Then meiosis can happen and turns it back into haploids (2) then mitosis to turn them into 8 total.  She explained to me that mapunits can be calculated to understand how far away from the centromere to determine where the coding is.  This helps someone to understand how recessive or dominant a gene is, based on the distance of map units.

Student: I explained how sordaria work and how they help deteremine map units as well as what map units are. It was decently hard to explain this to my mom because it is so strong in vocab and having to explain the words and what they do and trying to find ways to have her remember what they mean so I can explain the whole process more. It was helpful to me to explain the process more to my mom so I could work through it more myself and understand the process more.

Anne Sweeney
January 13, 2016 at 8:46pm

Parent: Anne taught me that sordaria are fungia and are used to find out map units. The sordaria undergo mitosis and meiosis. The sordaria have spores that are black and white. It is used to figure out map units as the formula for map units is (# of crossover asci) / (total # of asci / 2) x 100 = % (/2). The map units represents the distance from the sordaria from the centrosome; the farther the distance, the more crossovers occurred. Anne also taught me some of the vocab: Homozygous - the same alleles (ex.TT) Heterozygous - different alleles ( different combo); Genotype - genetic code; Phenotype - traits that are expressed.  

Student: I explained that sordaria helps us see the location of the genes on the chromosome. I talked about ow we use the map units formula and I spoke of the examples we did in class, counting the spores that cross and those that didn’t. The formula was easier to understand after I explained the reasons why for each variable. For the vocabulary I explained the roots of the words which made it easier to understand their meaning and function.

Piper Connell
January 09, 2017 at 7:23pm

Parent:  I appreciated learning about sordaria and how to use them in determining map units.  I could follow the flow from separate black and tan through meiosis and mitosis replication.   I also appreciated why determining map units is necessary and helpful in further research opportunities.

Student:  I taught my dad about sordaria and how we can track their black and tan genes through meiosis and mitosis by using the pictures in our lab book. I shared with him the formula for determining map units and what this means in terms of gene location on the chromosome. He had very good questions about why this would be important, which lead to conversations about the different options a scientist could choose to do after learning the location of a gene. By revisiting this information, I was able to solidify the formula and reasoning behind using the formula in my memory.

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