Trisomy The result of fertilization of sperm C with a normal egg containing the haploid chromosome number would be trisomy. We do not know what chromosome underwent nondisjunction, so we cannot be more specific.
Aberrant karyotypes containing an abnormal number of chromosomes are known in the human species. The best-known (and most common) chromosomal abnormality is trisomy 21, which is responsible for Down syndrome (mongolism). There are others such as Turner syndrome (woman with a single X chromosome) or Klinefelter syndrome (man XXY).
These abnormalities originate from the non-disjunction of the chromosomes of a pair of homologues during metaphase I of meiosis. At the end of division I, a daughter cell contains the two chromosomes of the pair considered and the other cell does not contain a chromosome of this pair. A similar result can be obtained during a bad distribution of chromatids during anaphase II.
After fertilization from a gamete of this type, a trisomy or a monosomy is obtained.
Is the sporophyte more prominent in mosses or liverworts? Are mosses gametophyte or sporophyte dominant? What is the adaptive significance of the seta of the sporophyte growing well above the mat of the gametophyte ? Better dispersal of spores
