Chakravarti A
Am J Hum Genet. 1983 Jul;35(4):592-610.
A marker locus closely linked to a disease locus is often useful for genetic counseling provided that a counselee is heterozygous at both disease and marker loci. Furthermore, the linkage phase of these genes in the counselee must be known. When the linkage between the disease and marker loci is very close, one often finds linkage disequilibrium between the loci. To evaluate the effect of such nonrandom associations on the utility of linked marker genes for genetic counseling, the proportion of informative families is studied for X-linked recessive and autosomal dominant diseases. This proportion is higher for X-linked genes than for autosomal genes, if other factors are the same. In general, codominant markers are more useful than dominant markers. Also, under appropriate conditions, the proportion of informative families is higher when linkage disequilibrium is present. The results obtained in this paper are useful for evaluating the utility of polymorphic restriction endonuclease cleavage sites as markers in genetic counseling.
与疾病位点紧密连锁的标记位点通常对遗传咨询有用，前提是咨询者在疾病位点和标记位点均为杂合子。此外，必须知道咨询者中这些基因的连锁相。当疾病位点和标记位点之间的连锁非常紧密时，常常会发现这些位点之间存在连锁不平衡。为了评估这种非随机关联对用于遗传咨询的连锁标记基因效用的影响，针对X连锁隐性疾病和常染色体显性疾病研究了信息性家系的比例。如果其他因素相同，X连锁基因的这一比例高于常染色体基因。一般来说，共显性标记比显性标记更有用。而且，在适当条件下，存在连锁不平衡时信息性家系的比例更高。本文获得的结果对于评估多态性限制性内切酶切割位点作为遗传咨询中的标记的效用很有用。
