SAMPLE APA PAPER FOR STUDENTS 2. Abstract. You may not have to include an abstract with your paper; if in doubt, ask your instructor. The. abstract is a single paragraph in block format (without paragraph indentation) and should be. between 150 and 250 words. Be sure to understand the difference between the abstract (a.
In the XY sex-determination system, the female-provided ovum contributes an X chromosome and the male-provided sperm contributes either an X chromosome or a Y chromosome, resulting in female (XX) or male (XY) offspring, respectively. Hormone levels in the male parent affect the sex ratio of sperm in humans.
Sex identification is an important part of generating a DNA profile. To determine sex from nDNA, analysts use the fact that females have two X chromosomes and males have one X and one Y chromosome to target genes that differ between males and females. Three common techniques in forensics focus on the SRY gene, the amelogenin gene and repetitive sequences on the Y-chromosome (Y-STR).