Genetics of Early Embryo Survival.

摘要

The albino-deletion complex represents one of the few regions of the mouse genome where a set of specific developmental defects are associated with a series of overlapping chromosomal deletions. A total of 37 deletions exist, all of which remove the region of mouse chromosome 7 that surrounds and includes the albino coat-color locus. The complementation patterns among these deletion chromosomes indicate that at least 9 distinct functional units exist in this region. Two of these units contain genes whose expression is required around the time the basic body plan is being established in the early postimplantation embryo. Embryos homozygous for the deletions that remove one of these units develop to day 8.5. Extensive development of the extraembryonic structures occurs, and the three primary germ layers form but there is no organization of mesoderm into somites or induction of the neural axis. Embryos homozygous for deletions that remove the second region, as well as the first, do not undergo gastrulation, and there is no development of the extraembryonic structures. 10 refs., 2 figs., 1 tab.