Packet 30 Flashcards
Genes with more than two alternate forms
3 different alleles of the I gene
IA, IB, or i
Multiple-Allele Inheritance
alleles are codominant since both genes are expressed equally
A and B
possible genotypes produce 4 blood types
6
4 phenotypes of the ABO blood groups are
A, B, AB, O
Traits controlled by many genes
continuous gradations ofsmall differences
body build, height andskin, hair & eye color
Polygenic Inheritance
controlled by 3 genes (Aa, Bb, Cc)
person with genotype of AABBCC is dark
person aabbcc is light
parental generation & F1 and F2 generation
skin color
23 pairs of chromosomes for a total of 46
- -each pair is homologous since contain similar genes in same order
- -one member of each pair is from each parent
somatics cells (diploid cells)
sex chromosomes are either X or Y
females have two X chromosomes
males have an X and a smaller Y chromosome
22 autosomes & 1 pair of sex chromosomes
single set of chromosomes for a total of 23
produced by special type of division: meiosis
gametes (haploid cells)
Genes found only on X chromosomes
sex-linked inheritance
is lack of either red or greencones, so seen as same color
XCXC is normal, XCXc is carrier
XcXc is color blind
XCY is normal, XcY is color blind
red-green color blindness
is sex-linked traitwhere blood fails to clot
hemophilia
result of environment effects on genetic makeup
more influential on polygenic traits such as height
phenotype
cause developmental defects
teratogens
fetal alcohol syndrome = slow growth, facial features, defective heart & CNS
cocaine = attention problems, hyperirritability, seizures
low birth weight, cleft lip & palate, SIDS
mental retardation, microcephaly
Chemicals & Drugs
Cigarette Smoking
Irradiation or radioisotopes during first trimester
10% of reproductive age U.S. population
- –ovarian disease or obstruction of uterine tubes
- –inadequate or excessive body fat
female infertility
definition is production of adequate quantities of viable, normal sperm & transport through ducts
—seminiferous ducts sensitive to x-rays, infections, toxins, malnutrition & high scrotal temperatures
Male Infertility
Alternative fertilization techniques
fertilization in a laboratory dish
embryo transfer
gamete intrafallopian transfer
mother given FSH to produce multiple oocytes (surgically removed)
mixed with solution containing sperm
in vitro fertilization
16 cell stage placed into uterus
fertilization in a lab dish
artificial insemination of oocyte donor
blastocyst transfer to infertile woman for pregnancy
Embryo transfer
FSH & LH stimulate multiple oocytes—aspiration & fertilization outside the body—reimplantation into uterine tubes (whole procedure is to skip vagina)
Gamete intrafallopian transfer
