TASK
The objective of this WebQuest is to prepare yourself to be an expert on sex-linked inheritance.
Due to you are an expert using the Internet... you will do bibliographic research to achieve the knowledge that will help you to solve the exercises proposed.
In the end, all the answers in PDF must be uploaded to your Class Group Paddlet before 10 days after starting the WebQuest.
The human species has 46 chromosomes grouped in 23 pairs of homologous chromosomes. 22 pairs are autosomatic, it means that are related to non-sexual characters, and one is a pair of sex chromosomes. In women are identified as XX and as XY in men. These chromosomes carry genes that determine the sex of the individual, and also other genes that influence hereditary characters not related to sex.
In the XY pair, one segment of each chromosome has particular genes, which is called a Heterologous segment or Non-Homologous. The remaining part of the chromosome corresponds to the Homologous, as in the autosomatic chromosomes. Therefore, in men (XY), the heterologous part of X chromosome will not have its homologous part in chromosome Y, whereas it will have its part in women. On the other hand, the heterologous part of the Y chromosome will never have a homologous, since there are no YY individuals.
Knowing these particular characteristics of sex chromosomes, we understand that there will be genes of the heterologous sectors in both chromosomes. These genes will be called GENES LINKED TO SEX. Those will show differences in patterns of expression depending if they are in women or men. The genes linked to the X chromosome will be expressed always in males, whereas in women if they are in homozygosis or if they are dominant. Finally, these genes linked to Y chromosomes will be expressed only in men.