PATTERNS OF INHERITANCE (4) Flashcards
genotype
specific genes for a particular trait (must be written in symbols)
dominant gene
will be expressed and will mask the recessive gene (Bb Tt Ao Bo Ff)
recessive gene
only shows up when homozygous recessive (bb tt oo ff)
alleles
genes for contrasting traits (Bb Tt Ao Bo)
homozygous
identical genes in a pair (bb/ BB)
heterozygous
different genes in a pair (Bb/ Ao)
phenotype
outward appearance of the offspring (written out in words)
- Bb: brown eyes
- Tt: tongue roller
- Ao: type A blood
- Ff: freckles
- bb: blue eye color
- tt: non tongue roller
- oo: type O blood
- ff: fair skin color
punnett square
- are the use of a grid to diagram crosses between individuals by using the possible parental gametes
- these allow one to determine the probability that an offspring will have a particular genotype and phenotype
monohybrid cross
an experimental cross in which parents are identically heterozygous at 1 gene pair
(Aa x Aa)
multifactoral trait
a polygenic trait that is particularly influenced by the environment
- skin color influenced by sun exposure
- height effected by nutrition
incomplete dominance
occurs when the heterozygote is intermediate between the two homozygotes
- CC x SS= CS
- curly hair x straight hair = wavy hair
codominance
occurs when alleles are equally expressed in heterozygote
- AA x BB = AB
- type A blood x type B blood= type AB blood
sex linked traits
traits controlled by genes on the sex chromosomes
- x-linked are carried on the X chromosome
- y linked are carried on the Y chromosome
duchenne muscular dystrophy
is characterized by wasting of muscles and death by age 20
fragile X syndrome
is the most common cause of inherited mental impairment
hemphilia
is characterized by the absence of particular clotting factors; blood clots very slowly or not at all
tay-sachs disease
lack of enzyme that breaks down fatty acid proteins in lysosomes results in accumulation
cysitc fibrosis
Cl- ions do not pass normally thru a cell membrane, resulting in thick mucus in lungs and other places, often causing infections
sickle-cell disease
red blood cells are sickle shaped rather than biconcave, resulting in clogged blood vessels
marfan syndrome
defect in the production of the elastic connective tissue protein fibrillan; results in dislocated lens, long limbs and fingers, caved in chest, and weak wall of aorta
huntington disease
huntington protein has too many gluatamine amino acids, leading to the progressive degeneration of brain cells
polypeptide
many protein
