Iris defects

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Part 2
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Pleiotropy one gene, many effects
Waardenburg Syndrome 2
MITF Defect in choroid fissure Drainage of
vitreous humor Microphthalmia
Iris defects Pigmentation defects Deafness Mast
cell deficiency
MITF
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Genetic heterogeneity many genes, same effects
(Stem cell factor)
(Sdf recceptor)
Reduced germ cell and blood cell migration
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Phenotypic variability one gene, different
effects
Black B_
Chocolate bb
Yellow B_ or bb with epistatic ee
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E_
B_
Yellow pigment Brown pigment Black pigment
bb
E_
Yellow pigment Brown pigment Black pigment
ee
Yellow pigment Brown pigment Black pigment
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FGF paracrine factors activate RTK pathway
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Gain-of-function mutation in FGF3 receptor such
that it is always on. Cartilage in growth plates
of long bones lead to premature differentiation
of the growth plate cartilage and shortened long
bones.
Velasquez, The Dwarf Francisco Lezcano, Called
"El Nino de Vallecas" Museo del Prado, Madrid
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Canonical Wnt pathway
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Hedgehog receptors and pathway
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http//infonet.com.br/biologia/aberracoes.htm
Shh from the prechordal plate suppresses Pax6
expression in the center of the embryo, dividing
the retinal field in two.
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Veratrum californicum
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Juxtacrine receptors and pathway
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In infants with Jarcho-Levin Syndrome, the trunk
may appear abnormally short due to fusion of many
vertebrae, incomplete development (dysplasia) of
one side of some vertebrae (hemivertebrae),
fusion of certain ribs, and/or other rib
malformations. Genetic defect is in Delta-like 3
gene.
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Infertility
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Infertility -- The inability to conceive after a
year of unprotected intercourse
Sterility -- An irreversible condition that
prevents conception.
Impotence -- The inability of the man to achieve
or maintain an erection and to ejaculate.
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Causes of infertility

• Tubal factor infertility
• Female age and egg quality
• Secondary amenorrhea
• Endometriosis
• Sperm defects
• abnormal sperm
• low sperm count
• sperm motility

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A dark, low quality egg with an irregular shape
from a 41 year old woman.
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The endometrium is the tissue that lines the
inside of the uterine cavity. Endometriosis is a
disease state in which some of this tissue has
spread elsewhere - such as to the ovaries, or
elsewhere in the abdominal cavity.
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A left fallopian tube that is blocked and dilated
with fluid From previous pelvic inflammatory
disease - PID
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Solutions Assisted Reproductive Technologies
(ART)

• AI (Artificial Insemination) Procedures
• IVF (In vitro Fertilization)
• GIFT (Gamete Intra-Fallopian Transfer)
• ICSI (Intra-Cytoplasmic Sperm Injection)
• Assisted Hatching

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Artificial insemination (IA)
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In vitro fertilization (IVF)

• Superovulation of mother or donor
• Recovery of mature egg from ovary
• Fertilization in Petri dish
• Incubation for 5 days
• Transfer of one or more embryos into uterus
• Hormone treatment (progesterone)

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Ultrasound image of ovary with many large
follicles
Aspiration of single follicle with needle (arrow)
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Healthy mature egg with follicle cells, ready for
addition of sperm
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Successfully-fertilized egg (two pronuclei and
second polar body)
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3
5
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Ultrasound image of embryo transfer. The uterus
is outlined in blue, the uterine lining circled
in red. The small black area (circled in yellow)
is fluid containing the embryos releasing from
the catheter (green)
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ICSI Intracytoplasmic sperm injection
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Gender selection
Jessica Collins was born on August 13, 1996 after
sperm separation for X-bearing (female) sperm
cells and simple medical insemination.
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Preimplantation Genetic Diagnosis
http//video.google.com/videoplay?docid7755799937
71535577qPGD
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http//www.ndsu.edu/instruct/mcclean/plsc431/marke
rs/marker1.htm
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RFLP (restriction fragment length polymorphism)
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Double-blind Test Aligned or Misalignedthat is
the question!
Aligned
Congression Failure
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http//video.google.com/videoplay?docid6519714054
634112418qmichaelJfox
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Cancer-causing mutations are of two types.

• Dominant Oncogenes
• Accelerator. Acts positively to STIMULATE
  proliferation. One mutation will do. There are
  about 100 known oncogenes (ras, src, etc.)
• Recessive Tumor-Suppressor Genes
• Brake. Acts negatively to STOP proliferation.
  Both alleles must be knocked out for cancer.
• the retinoblastoma gene (Rb) and p53 are two of
  several tumor suppressor genes

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