Textbook Assignment: Chapter 17, pages 490-519
Chapter 17 presents an analysis of the physical and molecular organization of a variety of genomes, ranging from those of the simplest viruses to human and other highly complex genomes. You are encouraged to read through the entire chapter. However, because part of this material is covered in MCDB 1150, and because of our partial coverage of many of the topics in other lectures, as well as our current lack of time, we will not discuss this chapter in classroom lectures at this time. However, we will return to some parts of it when we undertake an analysis of eukaryotic transcription control in lectures 37 and 38.
Previous coverage: In lecture 2, we briefly discussed the organization of eukaryotic DNA into chromosomes and the extreme amount of folding and compaction that must be achieved to make all of the DNA fit into the available space (Figure 17.9). As emphasized on page 497, the DNA in individual human chromosomes ranges in length from 17,000 micrometers (1.7 cm.) to 73,000 micrometers (7.3 cm.). For those who might wish to pursue this issue further, there is a web page that presents the exact size of each of the human chromosomes in megabases. Calculations based on this web page yield an even greater length for the largest human chromosomes.
We also discussed chromosome banding techniques (figures 17.13 and 17.14) both in lecture 2 and again in Lecture 14. Mitochondrial and chloroplast genomes were briefly examined in Lecture 16. The circular nature of bacterial chromosomes and their gene maps was discussed in Lecture 14. The organization of eukaryotic genes and control of their transcription was briefly examined in lecture 23, and will be further analyzed in 37 and 38.
Test coverage: You will not be tested on parts of chapter 17 that have not been covered in other lectures. However please be aware that we have touched on many of the topics in other lectures, including a number that have not been specifically listed above, such as VNTRs and other repeated sequences, telomeres and centromeres, chromatin, chromatin proteins, multigene families, heterochromatin, nucleosomes, etc. Also, some of this material is assumed background from MCDB 1150. Thus, you are well advised to achieve a reasonable level of understanding of the entire chapter if you do not already have it. The review questions for lecture 33 summarize those apects of the chapter that I think you should have an understanding of, based on exposure to the topics during other parts of the semester.