Chapter 17: Developmental Genetics

Caenorhabditis elegans

________ is a roundworm with mosaic development, a rigid developmental pattern in which the fates of cells are restricted early in development.

Nuclear equivalence

________ is the concept that, with a few exceptions, all the nuclei of the differentiated somatic cells of an organism are identical to one another and to the nudes of the single cell from which they descended.

Apoptosis

________ is programmed cell death.

Transgenic mice

________, in which foreign genes have been incorporated, have helped researchers determine how genes are activated and regulated during development.

C elegans

During development in ________, the anchor cell induces cells on the surface to organize to form the vulva, the structure through which the eggs are laid.

ABC

The ________ model of interactions among three kinds of genes hypothesizes how floral organs develop in Arabidopsis.

earliest developmental events

The ________ to operate in the egg are established by maternal effect genes in the surrounding maternal tissues, which are active prior to fertilization.

Gurdon

________ injected nuclei from tadpole intestinal cells into enucleated eggs; a small fraction of these eggs developed into tadpoles, demonstrating the totipotency of the injected nucleus.

Wilmut

________ fused a differentiated cell from an adult sheep cell with an enucleated egg and implanted it into the uterus of a host mother, where it developed into a normal lamb.

Steward

________ induced mature carrot root cells to become undifferentiated and express their totipotency, forming an entire plant.

Totipotency

________ is the capability of cells to direct the development of an entire organism.

laboratory mouse

The ________, M. musculus, is extensively used in studies of mammalian development.

human development

During ________, the human hand forms as a webbed structure, but the fingers become individualized when the cells between them die.

Transcription factors

________ are DNA- binding proteins that regulate transcription in eukaryotes.

mouse

The ________ shows regulative development; the very early embryo is a self- regulating whole and can develop normally even if it has extra or missing cells.

Developmental mutations

________ have been identified in the fruit fly, Drosophila, many of which affect the organism's segmented body plan.

Maternal effect genes

________ establish polarity in the embryo.

Embryonic stem (ES) cells, formed after a zygote has undergone several rounds of cell division to become a five

or six-day-old blastocyst, are pluripotent and have the potential to develop into any type of cell in the body; ES cells are not totipotent because they cannot form cells of the placenta