1. Concepts and Applications Seventh Edition
Powerpoint Lecture Outline
Human Genetics
Concepts and Applications
Seventh Edition
Ricki Lewis
Prepared by
Mary King Kananen
Penn State Altoona

2. Chapter 21 Reproductive Technologies

3. Advancing Technology Raises Ethical Dilemmas
Examples
Post mortem sperm retrieval
With and without donor consent
Sperm and oocyte banking
Cancer patients
Military personnel
Genetic testing of embryos prior to implantation
To identify lethal conditions
To provide a suitable umbilical stem cell donor

4. Assisted Reproductive Technologies
Methods that replace the source of a male or female gamete, aid fertilization or pregnancy
Developed to treat infertility but are becoming part of genetic screening
Examples
Surrogate pregnancy
In vitro fertilization
Sperm or egg donor

5. Infertility and Subfertility
Infertility is the inability to conceive a child after a year of frequent intercourse without contraceptives
Subfertility distinguishes couples who can conceive, but require longer time than usual
One in six couples have difficulty conceiving; 2.4 million couples in the U.S.
A physical cause can be identified in 90% of cases: 30% in males, 60% in females

6. Causes of Subfertility and Infertility in Men
Table 21.1

7. Causes of Subfertility and Infertility in Women
Table 21.1

8. Male Infertility One in 25 men are infertile
Easier to detect, but often harder to treat
Most cases of male infertility are genetic
Due to small deletions of the Y chromosome that remove genes important for spermatogenesis
Mutations in genes for androgen receptors or other hormones promoting sperm development
In cases of low sperm count, sperm can be stored frozen, then pooled
Lack of motility in sperm prevents movement in the female reproductive tract

9. Sperm Shape and Motility are Important
Figure 21.2

10. Sites of Reproductive Problems in Women
Figure 21.3

11. Female Infertility
Pregnancy of healthy women under 30 usually occurs within 3-4 months.
Irregular menstrual cycles can make it difficult to localize problems.
Tracking ovulation cycles aids determination of the most likely days for conception.
Fertility drugs stimulate ovulation but may induce release of multiple oocytes.
Blocked Fallopian tubes can result in ectopic pregnancy (tubal pregnancy).
Excess tissue growth in uterine lining
Fibroids: benign tumors
Endometriosis: buildup of uterine lining

12. Assisted Reproductive Technologies ART
Examples
Intrauterine insemination
Surrogate motherhood
In vitro fertilization (IVF)
Gamete intrafallopian transfer (GIFT)
Zygote intrafallopian transfer (ZIFT)
Oocyte banking and donation
Preimplantation genetic diagnosis

13. Intrauterine Insemination
Donated sperm in a woman’s reproductive tract, typically at the cervix or in uterus
Sperm catalogs list personal characteristics

14. Surrogate Motherhood
In surrogate motherhood, a woman carries a pregnancy to term for another woman who cannot conceive and/or carry the pregnancy
A surrogate mother may or may not have contributed an oocyte

15. In vitro Fertilization (IVF)
For in vitro fertilization or IVF, a sperm fertilizes an oocyte in a culture dish
Embryos are transferred to the oocyte donor’s uterus (or a surrogate’s uterus) for implantation
Intracytoplasmic sperm injection (ICSI) is more effective than IVF alone

16. Intracytoplasmic Sperm Injection
For cases in which sperm cannot penetrate the oocyte, IVF can be accompanied by ICSI which injects sperm directly into the oocyte
ICSI allows conception in cases of low sperm count, abnormal sperm shape, sperm motility problems
Figure 21.4

17. Gamete Intrafallopian Transfer (GIFT)
GIFT is a method in which superovulated oocyte from a woman and sperm from her partner are placed together in her uterine (fallopian) tube
Fertilization occurs in the woman’s body
Allows conception in cases of fallopian tube blockage
26% success rate

18. Zygote Intrafallopian Tube Transfer (ZIFT)
IVF ovum is introduced into the uterine tube and allowed to move to the uterus for implantation
GIFT and ZIFT are done much less frequently than IVF
Will not work for women with scarred uterine tubes
23% successful

19. Oocyte Banking and Donation
Oocytes, like, sperm can be stored frozen
New technique can freeze strips of ovarian tissue
Difficulties are possible because oocytes pause in meiosis II until fertilization occurs
Women can store their own oocytes
To have children later
Prior to undergoing chemotherapy
Work with toxins or teratogens
Donated oocytes can be used by women with infertility problems

20. Preimplantation Genetic Diagnosis
The technique of preimplantation genetic diagnosis (PGD) allows detection of genetic abnormalities prior to implantation
One cell or blastomere of an 8-celled embryo can be removed for testing. The remaining cells will complete normal development
1992 first child born following PGD to screen for cystic fibrosis alleles present in her family
PGD can be combined with IVF for women who have had multiple miscarriages

21. Preimplantation Genetic Diagnosis
Figure 21.5

22. Polar Body Biopsy
A polar body is a meiotic product from the same meiosis as the oocyte. Presence of deleterious allele in the polar body implies that the oocyte contains the normal allele of a heterozygous mother.

23. Table 21.3

24. ART Disasters Can Occur
Technology can create opportunities for extremely complex “families”
Multiple legal and ethical questions must be addressed
Examples of ART disasters in Table 21.4
Table 21.4