<u>What we already know:</u>
All species under normal circumstances will have two sex chromosomes. X and Y, Y is known to be dominant. All females will have two X chromosomes (XX, one X will always be given by the mother), whereas males will have one Y chromosome and one X chromosome (XY, one X will always be given by the mother. The father, on the other hand, could give either an X or a Y, that all depends on what sex chromosome the father's sperm donated.)
<em>So, how many chromosomes do a typical human have? Correct, a typical human has 32 chromosomes and only 2 of them are sex chromosomes. Now we must understand that the sex chromosome carries more than just the one code for the individual sex</em>.<em> That means that the gene codes for more than just the sex. </em>
<u>Building on that knowledge: </u>
<em>Sex-Related Inheritance</em> that differs from sex, is carried on one or two of an individual's sex chromosome. Whereas <em>Non-Sex-Related Inheritance</em> is carried on the other thirty chromosomes that the individual also carries.
<em>Sex-Related</em> inherited genes that are passed via the father to male offsprings, carried on the Y chromosome, are easiest to spot in a family. All males will have this trait and no females will.
Non-sex-related inheritance can be passed from male to female and from female to male, this is sometimes harder to differentiate from genes carried on the X chromosome because the mother always gives an X chromosome.
<u>Vocabulary:</u>
phenotype: the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.