MIDTERM TOPICS Flashcards
discovered that hereditary characteristics were determined by elementary units transmitted between generations in uniform predicatable manner
GREGOR MENDEL
Mendelian Principles
- principles of independent segregation
- principles of independent assortment
states that alleles in one gene pair separate clearly from each other during meiosis
exhibit monohybrid inheritance
principles of independent segregation
states that alleles of the different gene pairs separate clearly from each other and randomly combine during fertilization
exhibit dihybrid inheritance
principles of independent assortment
condition when one allele marks the expression of other allele
represented by a capital letter
dominance
expresses trait or character
dominance
allele that does not function when two different alleles are present in an organism
represented by a small letter
recessive
hidden traits or character
recessive
cells having different alleles at a given locus on homologous chromosome
Hh
heterozygous
cell having identical alleles at a given locus on a homologous chromosome
HH, hh
homozygous
physical expression of trait/character, physical outlook or organism
phenotype
genetic expression of trait/character, genetic makeup
genotype
cross between individuals that have different alleles at one gene locus
monohybrid inheritance
cross with only 1 trait
complete dominance
cross with 2 traits
incomplete dominance
Most common incomplete dominance
- tay-sach’s disease
- sickle cell disease
homozygosity for a recessive allele
tay-sach’s disease
failure to produce an enzyme hexosaminidase A
tay-sach’s disease
paralysis and degeneration of the retina
Tay-sach’s disease
death before age of 4
tay-sach’s disease
no treatment
tay-sach’s disease
caused by incompletely dominant alleles
sickle cell disease
caused by single nucleotide mutation resulting to abnormal hemoglobin
sickle cell disease
the cells can result in clumping and can interfere with blood circulation leading to local failures in blood supply
sickle cell disease
will result in damage to the heart, lungs, kidneys, muscles, joints, and brain
sickle cell disease
relationship of the alleles such that the phenotype of the heterozygote shows the individual expressions of each allele
co-dominance
two alleles affect the phenotype in separate and distinguishable ways
co-dominance
neither allele can mask the other and both are expressed in the offspring and not in the intermediate form
co-dominance
example of co-dominance
MNSs blood group system
the only recessive blood type
type O
what gene do we assume that a blood type has
heterozygous
what do we always use in determining the possibble blood type of an offspring
AO,BO
biological system that determines the development of sexual characteristics in an organism
sex determination system
how many pairs of homologous chromosome do we have?
23
how many pairs of autosome/non sex chromosome do we have?
22
how many pair of sex chromosome do we have?
1
sex of an individual is determined by:
X and Y chromosomes
inactive, densely stain condensed X chromosome located near the nuclear membrane in nuclei of somatic cells of XX females
barr body
medium sized type of sex chromosome
X
small size type of sex chromosome
Y
medium length type of sex chromosome
X
average length type of sex chromosome
Y
this sex chromosome is sub-metacentric
X
this sex chromosome is acrocentric
Y
the centromere of this chromosome is nearly central
X
the centromere of this sex chromosome is nearly terminal
Y
this sex chromosome does not have a banding
X
the type of banding Y chromosome has
fluorescent banding
has something to do with the nature of the chromosome
genetic sex
refers to the reproductive tissues and glands
gonadal sex
refers to the development of the genitalia and hormanal influence
genital sex
refers to the development of secondary sex characteristics which are influenced by hormones
somatic sex
refers to the attitude
sociophysiological sex
genetic characteristics determined by genes, which are located on the sex chromosome
sex linked traits
genes that are found on the sex chromosomes
sex linked genes
if a gene is located on y chromosome
Y-linked gene
genes only inherited by males
Y-linked gene
genes found on X chromosome
X-linked gene
can be inherited by both males and females
X-linked gene
the trait is transmitted by the mother to the son
X-linked recessive trait
expressed in males
X-linked recessive traits
Forms of X-linked recessive trait
- hemophilia
- color blindness
- albinism
- G6PD
- Lesch-Nyhan Syndrome
- Ectodermal Dysphasia (anhidrotic)
- Angiokeratoma (Fabry’s disease)
- Menke’s Syndrome
- Muscular Dystrophy
- Retinitis Pigmentosa
- Ichtyosis
- Hunter’s Syndrome
blood disorder in which certain blood clotting factors are not produced
hemophilia
result in excessive bleeding that can damage the organs and tissues
hemophilia
inability to form a blood clot due to lack of clotting factor 8
hemophilia A
characterized by the absence of clotting factor 9
hemophilia B
affected person is insensitive to red light about 25-45%
protan color blindness
the person is insensitive to green light about 60-75%
Deutan color blindness
trait is transmitted by father to his daughter
X-linked dominant trait
phenotype is expressed in both males and females who have an X chromosome that contains abnormal gene
X-linked dominant trait
refers to genetic conditions associated with mutations in genes on the X chromosome
X-linked dominant trait
traits that can only be inherited by the sons, never by the daughters
Y-linked traits
father to son transmission of trait
holandric genes
Most common Y-linked traits in human
- porcupine man
- webbed toes
- hypertichosis of the ears
a man in which the whole body is covered with rough, bristly scales (except soles, palms, head and face)
porcupine man
characterized by web-like connection between second and third toe
webbed toes
conspicuous growth of hair on the outer rim of the ears
hypertichosis of the ears
human traits that do not fall under the category of X and Y linked are considered sex limited and sex influenced genes
sex linked genes
inherited by both men and women but are normally expressed only in the phenotype of one of them
sex limited genes
pre existing dominance relationship between alleles that are altered according to the sex of the individual
sex influenced genes