Homeobox

In 1983, while studying Drosophila scientists discovered homeobox genes. A homeobox gene can contain a shared sequence that is 180 base pairs or 60 amino acids long referred to as the homeodomain. Homeobox genes have a multitude of functions including regulation of patterns, anatomical development (anterior-posterior), limb differentiation, the binding of DNA, and regulation of transcription. Due to the major role that homeobox genes play when it comes to providing the body plan for animals they are highly conserved evolutionarily. That high conservation has other means in regards to body plans developing over time. Conservation of homeobox genes is done well in segments which is part of the reason we know that there have been two complete…

Homeobox, also known as HOX genes, are genes that determine organ and limb formation during early embryonic development. Frances R. Goodman writes in his article “Limb Malformations and the Human HOX Genes” that humans have 39 HOX genes which are organized into four clusters. They have their own roles in the development of the central nervous system, axial skeleton, genitalia, and limbs. The study of HOX genes can lead to the identities of a number of human malformations. According to Shane C.…

Homeobox, or HOX genes are genes that determine organ and limb formation during early embryonic development. Frances R. Goodman writes in Limb Malformations and the Human HOX Genes that humans have 39 HOX genes that are organized into four clusters that have their own roles in the development of the central nervous system, axial skeleton, genitalia, and limbs. HOX genes were first discovered through mutation in fruit flies, which led to further research with HOX genes in other vertebrates. The…

The Dr gene has the MSX2 gene as an ortholog found in humans, which encodes the homeobox protein MSX-2. The protein plays an important role in craniofacial morphogenesis. A mutation in this gene is probably one of the reasons for craniosynostosis, which is a defect in babies head that prevents the brain to grow normally, resulting in a deformed head (Mozer, 2001). After several studies, Drop was proven an essential gene to neural development and cell differentiation. Mutations in this gene…

Cyclopia is a part of holoprosencephaly disorders which result from the failure of the forebrain to develop properly. Cyclopia presents as alobar holoprosencephaly which is the most severe form and one characterization of such a disorder is the lack of midline structures. The lack or abundance of tissue in the midface, prevents the two nasal primordia from joining the midline. When shh is expressed by the prechordal plate and ventral midline of the diencephalon, it causes Pax-6 expression in the…

of appendages and structures out of the pre-established segments. Induction is the process where neighboring groups of cells send chemical signals to one another in order to allow differentiation to move as a process. Apoptosis, or programmed cell death, is necessary to cellular development.. For example, the empty space between fingers in human is not there in early development. Thus, the hands are shaped like gloves or webbed feet. This structure is destroyed through apoptosis, which removes…

cytological atypia: PanIN-1, are composed of mucinous columnar epithelial cells with little cellular atypia; PanIN-2, are composed of papillary (rather than flat) epithelial and have some nuclear atypia; PanIN-3, have high-grade dysplasia and are referred to as carcinoma in situ (Figure 1.2) (19)(37). The histopathology of PDAC resembles ductal cells, and is where it derives its nomenclature. Although its nomenclature implies that the neoplasm originates from ductal cells, its exact…

known as Sahelanthropus Tchadensis around five to seven million years ago, the only way this assumption was made was through the discovery of fossils that were comparable to both humans and chimps. However, mice are also similar in their genetic makeup to humans; 85% is how genetically identical mice are to humans. The reason that this is possible is due to the fact that we have developmental regulatory genes, which activate the genes that puts the body parts together; telling them when and if…

develop gonadoblastoma[7]. If the DYZ3 locus is found on the Y chromosome using FISH, the risk of developing gonadoblastoma increases to 7 to 30 percent and gonadectomy should be performed if the DYZ3 locus is found in the gonadal tissue[5]. The exact loci and genes that cause the characteristics of Turner’s system are yet to be determined, but scientist think that the X chromosome plays an important role in the functionality of the ovaries, so when an X chromosome is missing, there may be a…

are capable of regenerating many tissues. There are several structures that they are able to regenerate which includes their limbs, tails, jaws, ocular lens, retina, parts of the heart and small intestines (Carlson, 2005). A lot of the specific molecules that play a role in regeneration still need to be discovered (Bryant, 2004). Observing newts and salamanders has enabled scientists to gain major insights into the mechanisms of tissue regeneration (Endo, 2004). The urodele model has provided us…