The Production of Homozygous Deficient Tissues with Mutant Characteristics by Means of the Aberrant Mitotic Behavior of Ring-Shaped Chromosomes.
نویسنده
چکیده
T IS the purpose of this paper to describe the method by which viable I tissues, homozygous deficient for a known region of a chromosome, r a y be produced in maize. The chromosomal region involved includes the locus of the gene Bm 1 in chromosome V (allele of bm 1, brown midrib, producing a brown color in the lignified cell walls). The lignified cell walls of the homozygous deficient tissue exhibit the features characteristic of the known recessive gene bm 1 although the locus of this gene is absent. The method of obtaining the hoaozygous deficient tissue is related to the unique behavior of ring-shaped chromosomes during soKatic mitosis. This behavior has been briefly mentioned in previous publications (MCCLINTOCK 1932 ; RHOADES and MCCLINTOCK 1935). Ring-shaped chromosomes do not always rr aintain themselves unaltered through successive nuclear cycles in the rraize plant. They rray (I) increase in size through duplication and reduplication of segrrents of the original ring, ( 2 ) decrease in size by deletions of segrrents from the ring, (3) be totally lost from the nuclei or (4) be present in increased numbers in the different nuclei. Whatever the method by which a change in size occurs, only ring chromosomes are produced from ring chromosomes. In maize i t has been found that deficiencies in certain regions of the
منابع مشابه
:.HE PRODUCTION OF HOMOZYGOUS DEFICIENT TISSUES ,’ WITH MUTAST CHARACTERISTICS BY ME-AX’S OF i \ THE ABERRANT MITOTIC BEHAVIOR OF RING-SHAPED CHROMOSOIMES*
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ورودعنوان ژورنال:
- Genetics
دوره 23 4 شماره
صفحات -
تاریخ انتشار 1938