Encounters: Turkey Day!

As many of you know, yesterday was Thanksgiving Day! Millions of American families sat down at the table yesterday evening and feasted upon the turkey and many many other dishes. It seems as if all the turkeys in America are fed well year round, preparing them for this one day special occasion. Being that in class we studied the development of chick eggs, I wondered if the development of turkey eggs would be the same? I mean it would make sense that most of the development of turkey eggs would be similar to that of chicken eggs. After-all, they both develop into birds...right?
Cleavage in chick eggs occurs through discoidal cleavage. Discoidal cleavage is a type of meroblastic cleavage that happens when a disk of cells are produced at the animal pole of the zygote. Cleavage only occurs in the blastodisc. Cleavage in the turkey egg is asynchronous and asymmetrical unlike the chick embryo. 
Have you ever thought about why we only chick eggs and not turkey eggs? The reason is because it takes a turkey a longer time to to lay the egg and it takes a longer time to hatch. Therefore chicken eggs are widely used, because they lay eggs at a faster rate and they take a shorter amount of time to hatch.

Reflections: Chick Embryology

Last week our class did a lab on the embryology of the chick. We had a chance to observe the development stages from the 13-18 hour chi to the 96 hour chick embryo. It was very interesting to follow one part of development and observe the changes as the chick embryo matured. I decided to follow the brain through its development. The brain begins its development at the 33-hour chick embryonic stage. It is at this stage that you can see the development of the telencephalon which will later be associated with the olfactory organs such as the smell and taste. The telencephalon will later develop into what we know as the cerebrum, which is important for intelligence. The diencephalon will give rise to the hypothalamus and the infundibulum which store the hormones oxytocin and antidiuretic hormone. The mesencephalon will become the process center of what can be seen and what is heard. The myelencephalon will give rise to what we know as the medulla oblongata which is reponsible for balance. As the chick moves onto its next stages, the brain becomes more and more mature and you can see the head folding. Below you can see the different parts in the developing 33-hour, 48-hour, 72-hour, and 96-hour chick embryo.

Encounters: Genotype XO

I work at a pediatrician's office, and about one to two weeks ago, a patient was born with a genotype of XO. This type of genotype is referred to as Turner Syndrome. It occurs when there is only one X chromosome and the other chromosome is not there at all. The patient's parents were very distraught, because they didn't know what to tell their friends and family members what the sex of the baby was. I found this very interesting because I have never knew of anyone with a genotype other than XX or XY. The doctor stated that in order for the infant to grow into a girl, she would need estrogen shots/pills to boost external female characteristics once she reaches puberty. It is not known whether she will be fertile or infertile, because that will be determined once she reaches the age of puberty.