Oak Anthracnose. Anthracnose is a general term used to describe diseases that result in a wide range of symptoms including leaf spots, blotches or distortion, defoliation, shoot blight, twig cankers and dieback on many different deciduous trees and shrubs. In most cases, anthracnose does not cause permanent damage to established trees.
1 Germ cells have only half the number of chromosomes as a diploid cell Â­ one of each pair-and are termed haploid (n) . 2  In a human egg or sperm, there are 23 chromosomes, one of which is an X or Y. 3  The number of chromosomes is reduced from 46 to 23 during the process of meiosis.
In Down syndrome, 95% of all cases are caused by this event: one cell has two 21st chromosomes instead of one, so the resulting fertilized egg has three 21st chromosomes. Hence the scientific name, trisomy 21. Recent research has shown that in these cases, approximately 90% of the abnormal cells are the eggs.