Biology 2581B Lecture Notes - Lecture 17: Cytosine, Reciprocal Cross, Noncoding Dna
Amazing division in genomic structure and content observed across bio world. In a broad sense we talk about the changed in genome architecture within or among groups. We also talk about the evolutionary forces responsible for these differences. Few thousand nt long to gigantic 100s of billions of nt long. Different structure circular, linear, or fragmented, where the genetic information is distributed on one or more than one chromosome. Copy # of each chromosomes some species are diploid with two copies of each chromosome, others, like many mitochondria, are polyploidy with many copies. Same chromosome can also be found in different conformations. Comprised of lots and lots of adenine and thymine nt (at-rich) or lots of guanine and cytosine nt (gc-rich) Some stretches have at-rich sequences while others have gc-rich sequences. Have lots of genes or only a few. Genes can be densely pact or separated by long stretches of noncoding dna in the genome.