1. KARYOTYPES NEWS Natalia Gonzalez Lopera School of Health Sciences
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4. I NTRODUCTION Cells, all time are trying to keep pace with constantly changing environmental conditions. They need that changes to strike a fine balance between maintaining their genomic integrity and allowing enough genetic flexibility to adapt to inhospitable conditions, because even a small change in this structure, such as an extra copy of a single chromosome, can lead to severe physical impairment. A healthy genome is characterized by 23 pairs of chromosomes.
5. Patterns of Chromosome Abnormality: The Key to Cancer? ScienceDaily (Jan. 23, 2012) The investigators have discovered that many chromosomal pairs are lost or gained together across various cancer types. The researchers discovered a new commonality of chromosomal aberrations among embryonic cancer types, such as kidney, skeleton, and liver cancers.
6. Some forms of cancer can even be diagnosed by identifying individual chromosomal aberrations . Patterns of Chromosome Abnormality: The Key to Cancer? ScienceDaily (Jan. 23, 2012) Researchers studied a collection of more than fifty thousand cancer karyotypes representations of chromosomal layouts in a single cell and charted them according to commonalities.
7. They confirm different chromosomal aberrations that appeared in specific cancer types, and for first time identified a broader effect of pairs of chromosomes being lost or gained together across different cancer types. Patterns of Chromosome Abnormality: The Key to Cancer? ScienceDaily (Jan. 23, 2012) It was also the first time that solid kidney, skeleton, and liver cancers share chromosomal characteristics and aberrations, much like various forms of leukemia or lymphomas.
8. In cancer, there are many cases of extra or missing chromosomes. Yet cancer cells thrive more effectively than other cells Cancer is the result of sequences of events, each causing the genome to become more mutated, mixed, and duplicated. Tracking these changes could aid our understanding of the driving forces of cancer's progress. Patterns of Chromosome Abnormality: The Key to Cancer? ScienceDaily (Jan. 23, 2012)
9. PERSONAL COMMENT I think that this investigation is very important because it can help us to understand more things about cancer (cancer development, pattern of mutation, etc..) that reveal more about progression of many different kinds of cancer. ScienceDaily ,January 2012
10. That Which Does Not Kill Yeast Makes It Stronger: Stress-Induced Genomic Instability Facilitates Rapid Cellular Adaption in Yeast ScienceDaily (Jan. 29, 2012) Stress itself can increase the pace of evolution by increasing the rate of chromosomal instability or aneuploidy. Cells employ intricate control mechanisms to maintain genomic stability and prevent abnormal chromosome numbers
11. Investigators found that under stress cellular mechanisms ensuring chromosome transmission fidelity are relaxed to allow the emergence of progeny cells with diverse aneuploid chromosome numbers, producing a population with large genetic variation. They found that natural selection picks the best choice under any given circumstance, arises independently of hostile environmental conditions, this is very interesting because it shows how stress itself can help cells adapt to stress by inducing chromosomal instability. That Which Does Not Kill Yeast Makes It Stronger: Stress-Induced Genomic Instability Facilitates Rapid Cellular Adaption in Yeast ScienceDaily (Jan. 29, 2012)
12. Aneuploidy is most often associated with cancer and developmental defects and has recently been shown to reduce cellular fitness. That Which Does Not Kill Yeast Makes It Stronger: Stress-Induced Genomic Instability Facilitates Rapid Cellular Adaption in Yeast ScienceDaily (Jan. 29, 2012) Euploid cells are optimized to thrive under 'normal' conditions. In stressful environments aneuploid cells can quickly gain the upper hand when it comes to finding creative solutions to roadblocks they encounter in their environment.
13. They show in a study that aneuploidy can confer a growth advantage on cells when they are exposed to many different types of stress conditions. The researchers say that is probable that stress could increase the chromosome segregation error rate. That Which Does Not Kill Yeast Makes It Stronger: Stress-Induced Genomic Instability Facilitates Rapid Cellular Adaption in Yeast ScienceDaily (Jan. 29, 2012) Investigators exposed yeast cells to different chemicals that induce various types of general stress and assessed the loss of an artificial chromosome. This initial screen revealed that many stress conditions, including oxidative stress, increased the rate of chromosome loss ten to 20-fold, other stress conditions make cells acquired an additional copy of chromosome .
14. PERSONAL COMMENT Is very important to know more about stress-induced chromosome instability because it can help us to understand how the cancer cells elude the body's natural defense mechanisms or the toxic effects of chemotherapy drugs. This study give us hope and the opportunity to combat 100% effectively the cancer in the future. ScienceDaily ,January 2012
15. MEDICAL UTILITY Some forms of cancer can be diagnosed easily by identifying individual chromosomal aberrations. Detecting changes in the genome such as mutation could aid our understanding of the driving forces of cancer's progress.
16. Various types of general stress, including oxidative stress, increased the rate of chromosome loss. MEDICAL UTILITY An example: skin cancer produced by exposition to sun
17. Adaptive genetic change, the concept of stress-induced genetic variation explains the bacterial drug resistance. Radicicol, a drug that induces proteotoxic stress, induced extremely high levels of chromosome instability in the yeast cell within a very short period of time. MEDICAL UTILITY
18. Continued growth of yeast cells in the presence of radicicol led to the emergence of drug-resistant colonies that had acquired an additional copy of chromosome XV. These cells also adapted more efficiently to the presence of other drugs including fluconazole, tunicamycin, or benomyl. MEDICAL UTILITY Tunicamycin-resistant yeast cells, which had adapted to the presence of the antibiotic by losing one copy of chromosome XVI, under drug-free conditions colonies had regained the missing chromosome. returning to a normal chromosome XVI number. T he fast growing yeast cells were no longer resistant to tunicamycin and thus clearly linking tunicamycin resistance to the loss of chromosome XVI.
19. BIBLIOGRAPHY Patterns of Chromosome Abnormality: The Key to Cancer?. ScienceDaily.2012, Jan. 23. That Which Does Not Kill Yeast Makes It Stronger: Stress-Induced Genomic Instability Facilitates Rapid Cellular Adaption in Yeast . ScienceDaily. 2012, Jan. 29.
