Define 1 Nondisjunction 2 Aneuploidy Fill in the Blank 3 I

Define

1. Nondisjunction –

2. Aneuploidy –

Fill in the Blank

3. In a deletion heterozygote the map distance between two genes may appear to be __________________ than it actually is.

4. ___________________ _____________________ is one way that recombination can lead to gene duplication.

True or False

5. Some genes on the X chromosome can escape inactivation and higher or lower dosage of these genes can lead to the phenotypes seen in individuals with sex chromosome aberrations.

6. Deleterious effects are more common when small autosomal chromosomes are added or deleted from the genome.   

Solution

(1) Non-disjunction =the failure of one or more pairs of homologous chromosomes or sister chromatids to seaparate normally during nuclear division , usually resulting in an abnormal distribution of chromosomes in the daughter nuclei ((2) ANEUPLOIDY = aneuploidy is the presence of an abnormal number of chromosomes in a cell,for example a human cell having 45 or 47 chromosomes instead of the usual 46.It does not include a difference of one or more complete sets of chromosomes ,which is called euploidy.