some crap about child dev.

1. Genetic Foundations and
Prenatal Environmental
Influences
Jan Augustine Paterno-
Yamsuan

3. Embryology
• The science of the development of
an embryo from the fertilization of
the ovum to the fetus stage.
• Carnegie stages are a standardized
system of 23 stages used to provide
a unified developmental chronology
of the vertebrate embryo.

4. Mitosis and Meiosis

5. Interphase
• During interphase the chromosomes are
dispersed in the nucleus and appear as a
network of long, thin threads or filaments,
called the chromatin. At some point before
prophase begins, the chromosomes
replicate themselves to form pairs of
identical sister chromosomes, or
chromatids; the deoxyribosenucleic acid
(DNA) of the chromosomes is synthesized
only during interphase not while mitosis is
in process.

6. Prophase
The two chromatids remain attached to one
another at a region called the centromere,
but each contracts into a compact tightly
coiled cell body.; the nucleolus, and in
most cases, the nuclear envelope breaks
down and disappears. Also during this
phase, spindle begins to form. In animal
cells the centioles separate and move
apart, and radiating bundles of fibers,
called asters, appear around them.

7. Metaphase
• Chromosomes congregate at a plane
midway between the two ends to
which the spindle tapers. This is
called the equatorial plane and
marks the point where the whole cell
will divide when nuclear division is
completed, the ends of the spindle
are the poles to which the
chromatids will migrate.

8. Anaphase
• Two chromatids of each
chromosome separate and
move to opposite poles, as if
pulled along the spindle fibers
by the centromeres.

9. Telophase
• New nucleoli begin to appear,
and eventually, as the formation
of the two daughter nuclei is
completed, the spindle fibers
disappear. The chromosomes
uncoil to assume their
dispersed distribution within the
interphased nucleus.

10. • Gene: molecular unit of hereditary of
a living organism.
• Phenotype: composite of an
organism’s observable traits.
Phenotypes result from the
expression of an organism’s genes
as well as the influence of
environmental factors and the
interactions between the two.

11. • Genotype: genetic make up of
an individual.
• Allele: one of a number of
alternative forms of the same
gene or same genetic locus.

12. Environmental
Influences
• Teratogens : substances or
environmental agents which
cause the development of
abnormal cell masses during
fetal growth which result in
physical defects in the fetus.