Heredity
2. The passing on of certain inherited characteristics from one
generation to another.
1.What is heredity?
3. Hair
Eyes
Height
Intelligence
Talents
Dimples
2.Name 3 characteristics that can be hereditary.
4. Defective gene from one or both parents
Downs Syndrome
Hemophilia
Muscular Dystrophy
Sickle Cell Anemia
Cleft Palate
Cystic Fibrosis
Spina bifida
Hereditary Birth Defect
5. 46 chromosomes carry thousands of genes.
Contain all the characteristics a person will have.
3.What is the relationship between chromosomes and genes?
6. Males have XY chromosomes
Females have XX chromosomes
Egg and Sperm cells have only 23 chromosomes
All eggs are X, sperm can be X or Y
Sperm cell from father determines sex of baby
4.How is the sex of the child determined?
7. Sex Determination
8. Chromosome:Threadlike particles in nucleus of cell which carries
hereditary factors.
Genes:Part of the chromosome that determines all inherited
characteristics
5.Terms to Define
9. Dominant:Stronger gene that determines appearance of a
trait.
Recessive:Weaker gene; will not appear when paired with a dominant
gene
10. 11. 6.At the moment of conception, every human baby receive 46
tiny chromosomes.23 from the sperm/father, 23 from the egg of the
mother.
7. At Conception:the fertilized egg has instantly acquired all the
physical traits its parents can ever give it.
12. Dominant & Recessive Gene Combinations for Eye Color
Brown-eyedBlue-eyed
13. A.Identical twins:1 egg + 1 sperm -- splits into two children,
must be the same sex.
B.Fraternal Twins:2 eggs + 2 sperm both fertilized; can be same sex
or one of each.
C.Siamese Twins:Conjoined twins 1 egg + 1 sperm split, however the
split does not completely occur.
8.Explain how the following occur:
14. Identical Twins:
One fertilized egg splits in half, each half develops intoa
separate embryo.
Happens soon after fertilization
Offspring share DNA, they are the same sex
ONE EGG, ONE SPERM, ONE PLACENTA
Fraternal Twins:
Two eggs are released at same time, each fertilized by different
sperm.
No more alike genetically than any siblings
TWO EGGS, TWO SPERM, TWO PLACENTAS
Multiple Births.
15. 16. ONE EGG, ONE SPERM
EGG STARTS TO SPLIT AS IN IDENTICAL TWINS, BUT DOESNT COMPLETE THE
SPLIT.
EMBYROS WILL DEVELOP ATTACHED
can be extremely traumatic
approximately 40-60% of these births are delivered stillborn with
35% surviving just one day.
overall survival rate between 5-25%
historical records over the past 500 years detail about 600
surviving sets of conjoined twins with more than 70% of those
surviving pairs resulting in female twins.
CONJOINED TWINS
17. 18. 19. Eng and Chang Bunker, The Siamese Twins
There is an extremely rare form of identical twins that occurs
perhaps in one out of every 75,000 to 100,000 births or 1 in 200
deliveries of identical twins, that of conjoined twins.Conjoined
twins originate from a single fertilized egg so they are always
identical and same-sex twins. The developing embryo starts to split
into identical twins within the first two weeks after conception
but then stops before completion, leaving a partially separated egg
which continues to mature into a conjoined fetus.
The most famous set of conjoined twins were Chang and Eng, the men
who originated the term "Siamese Twins". Eng and Chang were born in
Siam (modern day Thailand) on May 11, 1811 to a Chinese father and
half-Chinese, half-Malay mother. Thanks to their heritage, while
growing up in Siam the boys were known as "The Chinese
Twins".Despite the fact that their birth was initially believed to
be an omen of the end of the world, they brought celebrity to their
small village. Their mother refused to allow doctors to attempt to
separate the boys, fearing that to do so would result in the death
of one or both. Instead she taught them to stretch the tissue that
joined them so that they could stand side-by-side rather than
always face-to-face.
20. Chang and Eng began to date Adelaide and Sarah Ann Yates, two
of nine daughters of local farmer and part-time clergyman, David
Yates. The townspeople disapproved, so Chang and Eng scheduled a
separation surgery in Philadelphia. Their fiances found out and
quickly stopped the proceeding, and in April, 1843, Chang was
married to Adelaide and Eng to Sarah Ann in a double wedding.
During the course of their marriages, Eng fathered six boys and
five girls; Chang seven girls and three boys. All were normal
except for a son and daughter of Chang's who were deaf mutes.
In January, 1874, Chang Bunker died after a severe case of
bronchitis, possibly from a cerebral clot. Eng died shortly
thereafter.
After their deaths it was determined they could have been
successfully separated, a medical option that was never offered to
Eng and Chang during their lives.
21. Although Eng and Chang's fame helped coin the phrase 'Siamese
Twins', they were not the first pair of conjoined twins recorded in
medical annals as there were probably about 100 such pairs known by
the time of their 1811 births, a fact which helped the King of Siam
reverse an early death sentence on the brothers. In fact, conjoined
twins were recorded as early as 945 in Armenia and the first pair
of successfully separated twins took place in 1689 by German
physician G. Knig.
The birth of two connected babies can be extremely traumatic and
approximately 40-60% of these births are delivered stillborn with
35% surviving just one day. The overall survival rate of conjoined
twins is somewhere between 5-25% and historical records over the
past 500 years detail about 600 surviving sets of conjoined twins
with more than 70% of those surviving pairs resulting in female
twins.
22. How common are twins and other multiple pregnancies?These days,
about one in 32 births are twin births. This rate has gone up 65
percent since 1980, and it's more than double the rate among women
who conceive without medical assistance one in 89.The rise in
triplets and quadruplets is even more dramatic. Between 1980 and
1998, the rate of triplets and higher-order multiple births shot up
by more than 400 percent, but it's crept back down over the past
few years as fertility treatments have become more refined. In
2003, one in 535 births resulted in triplets, quadruplets, or
more.Meanwhile, the likelihood of having identical twins (when one
fertilized egg divides in half) is about one in 250. This rate
hasn't changed over the decades and is remarkably constant all over
the world.
23. 9.What is the relationship between infertility and fertility
analysis?
Infertility:Problems of conception or implantation have
occurred
Fertility Analysis:What options does a couple have
24. Fertility Drugs
Artificial Insemination Sperm is injected into woman's
uterus.
IVF (Invitro-Fertilization) Sperm and egg are fertilized outside of
body and then placed in the uterus Test tube baby very expensive
with only a 80-90% chance of pregnancy.Variation: Ovum
transfer
Surrogate Mother:Carries fertilized egg through IVF for couple or
may be artificially insemination byfathers sperm
Adoption
1o.List 5 options for an infertile couple
25. An abnormality that affects the structure or function of the
body.
Hereditary & Environmental
11.What is a Birth Defect?
26. Any pregnancy that ends due to natural causes before the
embryo/fetus could possibly survive on its own.
20% of pregnancies end in miscarriage
After 20 weeks, known as a stillbirth
12.What is a miscarriage?
27. Anything affecting the fetus by what the mother has done while
pregnant;poor nutrition, alcohol, drugs, x-rays etc.
13.Environmental Birth Defect
28. Downs Syndrome:21st chromosome pair has 3 chromosomes instead
of usual 2
15.Birth Defect caused by an error in chromosomes
29. Mother and baby have different blood types;
Example:Mother RH -,Father RH +,= Baby RH+
Mother will have an RH different from her own after labor and
delivery and her body will begin to make antibodies to fight of
this intruder
Next baby is rejected by mothers immune system.
16.Explain what RH Incompatibility is.
30. Informs parents in advance the odds that their children will
have a certain disease.
Parents suspect a problem from:
Medical/Family History
Physical Exam
Lab Tests
17.How can a genetic counselor help prospective parents?
31. Amniocentesis:Needle inserted through belly button withdraws
amniotic fluid;Recommended for women over 35.
Ultra Sound Sound waves make an image to insure fetus is developing
normally.
Chorionic Villi Sampling:Catheter goes through vagina into uterus
for sample of tissue from membrane encasing fetus;Can find out
results much sooner that amniocentesis.
18.List and explain 3 genetic tests for diagnosing birth
defects.
32. 19.Environmental Hazards to avoid during pregnancy and explain
their potential dangers.
Alcohol FAS,Women should not have any amount
Over the Counter Medications:Aspirin, Ibuprofen etc.May cause
problems for baby
Caffeine:Coffee, tea, sodas, chocolate;
Tobacco:Premature & Low birth weight
Illegal Drugs:Serious addictions and brain damage
X-rays:Radiation; make sure to tell Doctor or Tech.
Rubella or German Measles: Vaccine now
STDs :Birth defects or blindness etc.
Other Infections:Should always discuss with doctor.
33. Addiction passed on to fetus
Prematurity and low birth weight
Withdrawal painful and may even cause death
Birth defects
Learning Disorders
20.Explain how the use of drugs could affect the development of the
fetus during pregnancy
34. END