Copyright information:  information content copyright owned by Cat World expires 70 years from March 1973 at which time the information minus the research notes may be placed in the public domain.
Research Note:  Here is an article which has been partially converted for online presentation.  It is from the March/April 1974  issue of Cat World which holds the copyright for the text.  This text has not been split into separate files so that it makes for easier printing.  Question:  Is it better to allow for printing or optimize for reading and information chunking.  Note the graphics additions to visually break the text.  Note the bolding of terms and the links to other information -- which add a new original dimension to the work and enhance the information offering.

Cell Division

As has been explained the nucleus of the fertilized ovum contains one set of chromosomes derived from the sire and one set of chromosomes derived from the dam. So will all other cell nuclei subsequently formed by normal cell division. In the development of the kitten embryo the cells divide in a manner resulting in all the daughter cells retaining the diploid number of  38 chromosomes and this type of cell division is called mitosis or normal cell division. But there is the special type of cell division that occurs just before the gametes are formed and this results in the daughter cells having the haploid number of chromosomes. This special type of cell division is called meiosis or reduction cell division. Mitosis therefore results in daughter cells with the same complement while meiosis results in daughter cells with half the chromosome complement. The stages leading to the final inheritance of 38 chromosomes are as follows:

  1. The division of diploid cells carrying 38 chromosomes each into diploid daughter cells also carrying 38 chromosomes each (mitosis);
  2. The division of diploid cells carrying 38 chromosomes each into haploid cells carrying 19 chromosomes (first stage of meiosis);
  3. The differentiation of the haploid cells into ova and spermatazoa, i.e. the gametes (second stage of meiosis);
  4. The fertilization of the ovum by the spermatozoon resulting in the zygote in which the diploid number of chromosomes is restored.
Cell Division
Mitosis Meiosis
Male Female Stage Male Female Stage
Stage 1: Diploid cells of male and female
(38 chromosomes)
Stage 1: Diploid cells of male and female
(38 chromosomes)
Stage 2: After mitosis or normal cell division there are still 38 chromosomes in each cell Stage 2: Haploid cells of male spermatozoon and female ova with 19 chromosomes
Fertilization
Stage 3: Diploid cells of kitten embryo with 38 chromosomes

The zygote (fertilized ovum) develops into the kitten embryo whose cells continue to divide in the normal manner until the cells in the mature cat divide by reduction division preparatory to forming gametes awaiting fertilization to produce the next generation and so on ad infinitum.