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In general, nondisjunction can occur in any form of cell division that involves ordered distribution of chromosomal material. Higher animals have three distinct forms of such cell divisions: Meiosis I and meiosis II are specialized forms of cell division occurring during generation of gametes (eggs and sperm) for sexual reproduction, mitosis is the form of cell division used by all other cells ...
The extra chromosome is retained because of a nondisjunction event during paternal meiosis I, maternal meiosis I, or maternal meiosis II, also known as gametogenesis. The relevant nondisjunction in meiosis I occurs when homologous chromosomes, in this case the X and Y or two X sex chromosomes, fail to separate, producing a sperm with an X and a ...
The discrepancy can be resolved by testing the person's red blood cells with an anti-A 1 reagent, which will give a negative result if the patient belongs to the A 2 subgroup. Anti-A 1 antibodies are considered clinically insignificant unless they react at 37 °C (99 °F). Other subgroups of A exist, as well as subgroups of B, but they are ...
We denote the chromosomes carrying translocated material with a T and the chromosomes with a normal order of genes with an N. Chromosomes N1 and T1 have homologous centromeres found in wild type on chromosome 1; N2 and T2 have centromeres found in wild type on chromosome 2. During anaphase of meiosis I, the mechanisms that attach the spindle to ...
The S antigen is relatively common (~55% of the population) and the s antigen is very common (~89% of the population). Anti-S and anti-s can cause hemolytic transfusion reactions and hemolytic disease of the newborn.The U antigen is a high incidence antigen, occurring in more than 99.9% of the population.
Early in meiosis 1, Ime2 activity rises and is required for the normal accumulation and activity of Ndt80. However, if Ndt80 is expressed prematurely, it will initially accumulate in an unmodified form. Ime2 can then also act as a meiosis-specific kinase that phosphorylates Ndt80, resulting in fully activated Ndt80. [26]
The XG antigen is a red blood cell surface antigen discovered in 1962. [1] by researchers at the MRC Blood Group Unit. [2] The PBDX gene that encodes the antigen is located on the short arm of the X chromosome. [3] [4] Since males normally have one X chromosome they are considered hemizygotes.
[2] In the case where the sperm is the genetic cause of 48,XXXY syndrome, the sperm would have to contain two X chromosomes and one Y chromosome. This would be caused by two nondisjunction events in spermatogenesis, both meiosis I and meiosis II. The duplicated X chromosome in the sperm would have to fail to separate in both meiosis I and ...