Tim and Stephanie are devastated when they find out their newborn son has hemophilia- sex-linked recessive disease. Tim is shocked because he doesn’t have hemophilia, and figured if his son has it he would have gotten it from him. Is Tim correct in his thinking? Explain. Also explain what their genotypes must be in order for neither parents to have the disease but their son does. Create a Punnett square, and indicate the mother's and father's genotype.

Hemophilia is a X-linked recessive disease. Tim is not correct in his thinking because he can not pass the condition to his son. Only mother can pass it to sons since they get X chromosome from the mother. Father gives Y chromosome to sons which does not carry the hemophilic gene.

Tim and Stephanie's son can be hemophilic even when neither of the parents are hemophilic. In this case, Stephanie must be a carrier i.e. heterozygous for the trait.

Tim : XHY (normal)

Stephanie : XHXh (normal but carrier)

Their children:

        XH          Y

XH  XHXH   XHY

Xh   XHXh   XhY

As clear by the punnett square, all the daughters will be normal (half will be carriers like Stephanie). Half of the sons will be normal (XHY) and other half will have hemophilia (XhY).

1. dermis

2. chemical

3. urine

4. viruses

5. antibodies

picture a world where computers are building made-to-order personalized robotic arms and synthetic organs, drones are circulating above mars! due to the rapid growth of technology, the future has never been more unpredictable, and it presents a huge challenge in education: we are teaching students how to work in a future that we have never been unsure of. it is widely predicted that in eight years’ time, there will be more jobs in the fields of science, mathematics, technology and engineering than in any other discipline. and, as the technology continues to develop, it will soon become clear that addressing social problems will involve more innovative thinking, and analytical and technical knowledge than ever before. undeniably, there are no subjects that encourage innovative and creative thinking, deep thought, problem solving and independence more than the stem subjects. while it is widely commented on that there is a need to reimagine the ways stem subjects are taught in schools by embracing a more interactive and innovative approach to appeal to more students, it should come as no surprise that some of the most reputable educational organizations in the world are already implementing changes to embrace stem. harvard, for example, announced in 2014 that they were increasing their computer science faculty by over 50% and has since introduced computer science as a core subject for all freshmen. the urgency of supporting stem subjects at a young age is becoming more relevant than ever, as adopting a keen interest in the curricula needs to happen early. however, beyond the age issue is one of gender.

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