Genetics: Analysis of Genes and Genomes: Keyword Hot Links for chapter 5

The linkage map of the human chromosomes currently includes more than 5,000 genetic markers. Detailed linkage maps of the human chromosomes are available in graphical format at this keyword site. The site also includes tables of the physical length of each chromosome in nucleotide pairs, the genetic length in centimorgans in males and females, and the number of informative meioses that are required to yield statistically significant lod scores for any specified recombination fraction.

The database SGD includes information on the molecular biology and genetics of Saccharomyces cerevisiae, commonly known as budding yeast or baker's yeast. Genetic linkage analysis remains an important tool in this organism even though its DNA sequence is completely known. Genetic research is often driven by the discovery of a new mutation that exhibits an arresting phenotype, and the first step in the analysis is to map the mutation genetically to learn its position and ultimately its identity. The keyword tetrads will access extensive listings of the numbers of parental ditype, nonparental ditype, and tetratype tetrads observed in two-point crosses.

One of the earliest cases of genetic linkages in a human autosome, reported in 1965, was that between the ABO blood-group gene and a gene which, when mutated, causes nail-patella syndrome NPS. The frequency of recombination is about 10% but is higher in females than in males. At this keyword site you can learn more about NPS as well more recent linkage data and the lod scores on which the inference of linkage is based.