Eyre-Walker A
Institute of Cell Animal and Population Biology, University of Edinburgh, U.K.
Proc Biol Sci. 1993 Jun 22;252(1335):237-43. doi: 10.1098/rspb.1993.0071.
Several lines of evidence are presented which suggest that sequence G + C content and recombination frequency are related in mammals: (i) chromosome G + C content is positively correlated to chiasmata density; (ii) the non-pairing region of the Y chromosome has one of the lowest G + C contents of any chromosomal segment; (iii) a reduction in the rate of recombination at several loci is mirrored by a decrease in G + C content; and (iv) when compared with humans, mice have a lower variance in chiasmata density which is reflected in a lower variance in G + C content. The observed relation between recombination frequency and sequence G + C content provides an elegant explanation of why gene density is higher in G + C rich isochores than in other parts of the genome, and why long interspersed elements (LINES) are exclusive to G + C poor isochores. However, the cause of the relation is as yet unknown. Several possibilities are considered, including gene conversion.
现有多条证据表明，在哺乳动物中，序列G + C含量与重组频率相关：（i）染色体G + C含量与交叉密度呈正相关；（ii）Y染色体的非配对区域是所有染色体片段中G + C含量最低的区域之一；（iii）几个基因座处重组率的降低与G + C含量的降低相对应；（iv）与人类相比，小鼠交叉密度的方差较低，这反映在G + C含量的方差较低。观察到的重组频率与序列G + C含量之间的关系，为富含G + C的等臂染色质中基因密度高于基因组其他部分，以及长散在元件（LINEs）为何仅存在于G + C含量低的等臂染色质中，提供了一个合理的解释。然而，这种关系的原因尚不清楚。考虑了几种可能性，包括基因转换。
