How do we know that X chromosomal inactivation of either the paternal or maternal homolog is a random event during early development in mammalian females? Select all that apply.   a. Studying the electrophoretic variants of glucose-6-phosphate dehydrogenase.   b. Using test crosses involving females possessing different genetic markers in sex chromosomes.   c. Cytological studying during the blastocyst stage of development.   d. Observing the mosaic coat patterns inheritance.   e. Using electronic microscopy to track the inactivation of X chromosome.

Molecular geneticists have performed experiments in which they altered the number of copies of the bicoid gene in flies, affecting the amount of Bicoid protein produced. a. What would be the effect on development of an increased number of copies of the bicoid gene? b. What would be the effect of a decreased number of copies of bicoid? Justify your answers.

The following are various developmental phenomena relating to the concepts and principles in developmental biology. A. Concept of apoptosis B. Concept of prefomed guidelines C. Concept of programmed gene action D. Concept of capacity E. Concept of fate F. Concept of environmental influences G. Concept of induction H. Concept of progressively formed guidelines I. Concept of Differentiation J. Concept of guidelines K. Concept of Gradient L. Concept of differentiation Question #1. During the cleavage stage, the masked messenger RNA from the developing oocyte controls the cleavage patterns. During the blastula stage, specific genes are activated; hence there is appearance of new proteins. What concept? Question #2. Catfish collected in the polluted waters of Pampanga River were found to have ruptured and vascularized brain. What concept? Question #3. Stem cell technology is based on the principle that an undifferentiated cell is totipotent. What concept?

Possible options:  A. Autopolyploidy B. Allopolyploidy C. Chromosome duplication D. Pericentric inversion