BIOL308 Study Guide - Sister Chromatids, Dna Replication, Metaphase
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Which of these statements is incorrect?
Syntenic genes are located on the same chromosome. |
Independent assortment results in recombinant chromosomes. |
You can reliably predict the relative genetic distance fromgenes’ physical distance on a chromosome. |
Linked genes are always syntenic. |
What is the relative genetic distance between two linked genesif the recombination frequency is 0.49?
0.49 cM |
4.9 cM |
49 cM |
490 cM |
What statement best explains the distortion in Mendelian ratiosobserved by Bateson & Punnett in 1905? (Reminder: they found anoverrepresentation of F2 offspring showing both dominant orrecessive phenotypes, and an underrepresentation of offspringdisplaying one dominant and one recessive phenotype)
| Human error: they should have been more careful about theirexperimental setup. |
| Gene linkage: Genes for flower color and pollen shape arephysically close on the same chromosome, leading to a breakdown inthe independent assortment of the alleles for these traits. |
| Chromosome crossover: Homologous recombination of twochromatids during meiosis caused the alleles to shuffle, resultingin a breakdown of the independent assortment of the alleles forthose genes. |
Random variation: No two situations are alike. In finitepopulations, you are going to get some variation across a mean. |
When determining the relative genetic distance between twogenes, why is dihybrid back-cross preferable over traditionaldihybrid cross?
| 9:3:3:1 phenotypic ratio is easier to work with than 1:1:1:1ratio. |
| Genotypes of the offspring can be determined based on theirphenotype. |
If the genes are independently assorted, the dihybrid back-crosswould result in only 2 genotypes in the F1 generation. |
B and C |
Why do we map genes?
| To understand how genes interact with each other |
| Comparative genomics analysis |
| To determine the genotype of an organism |
| All of the above |
I'll be thankful if someone can help me to do this!
According to this:
Read the following New York Times article and then answer the questions below and then answer the questions New Clues to Sex Anomalies in How Y Chromosomes Are Copied
http://www.nytimes.com/2009/09/15/science/15chrom.html?scp=1&sq=sex%20anomalies&st=cse
This activity contains 5 questions.
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You must make 2 reflective, thoughtful, deep, constructive critiques of your class mates posts. as part of a threaded discussion following their initial post. The critiques must not about you, but about science!
Here's the first peson. Needs to reply for some of her answers as it says above.
1. When discarding bad genes, the Y chromosomes recombines with itself.
2. The centromere functions to hold a pair of copied chromosomes together.
3. A person with Turner’s syndrome is born with a single X chromosome.
4. The male-determining gene on the Y chromosome is located close to the end of the left arm.
5. An individual can have some cells with no Y chromosomes and other cells with double Y chromosomes, due to the differing variants present in regards to the genotypes of the cells in a single individual. When the Y chromosome is compared to other chromosomes such as the X chromosome, mutations and deviation in the distance of the centromere are much more prevalent due to the Y chromosome lacking a backup system to promote repairs.1 (Links to an external site.) Even if a mutation caused a condition such as the XYY syndrome where two Y chromosomes are present, that mutation and genotype would not be present in every single cell of the individual.2 (Links to an external site.) The presence of different genotypes offers an tentative explanation to as why a single individual can have some cells with no Y chromosomes while also housing other cells with double Y chromosomes.
Source 1 http://www.nytimes.com/2009/09/15/science/15chrom.html
Source 2 https://www.healthline.com/health/xyy-syndrome
Here's the second person. Needs to do the same as it says above.
1. Itself
2. Centromere
3. A single X chromosome
4. Close to the end of the left arm
5. Briefly explain how an individual can have some cells with no Y chromosome and other cells with a double-Y chromosome.
In some cases, the Y chromosome reaches over to a neighboring counterpart and the two chromosomes fuse. This results in the loss of part of the chromosome. Jacob’s Syndrome is sometimes also called XYY syndrome because the person has two Y chromosomes. Although a person can survive with this genetic mutation, some physical traits may be observed such as taller than average height, weak muscle development or late speech development.
Source 1 https://www.healthline.com/health/xyy-syndrome
Source 2 http://www.isna.org/faq/y_chromosome