Mendell's Study Guide #3 Flashcards
there are three different alleles for a blood group A, B, and O but an indiidual has only two at a time
multiple alleles
crosses between cremello (off-white) horses always produce cremello offspring. crosses between chestnut (brown) horses always result in chestnut offspring. a cross between chestnut and cremello horses produces palomino (a golden-yellow color somewhat intermediate between chestnut and cremello_ offspring. If two palominos are mated, their offspring are produced in the ratio of 1 chestnut: 2 palominos: 1 cremello
incomplete dominance
the sickle-cell, s, is responsible fora variety of phenotypic effects, from pain and fever to damage to the heart, lungs, joints, brain, or kidneys
pleiotropy
in rabbits, an allele for ful color (C) is dominant over an allele for chinchilla (c’) color both full color and chinchilla are cdominant over the white allele (c). a rabbit can be CC, Cc’, c’c’, c’c, or cc
multiple alleles
in addition to the A and B molecules found on the surface of red blood cells, humans also have M and N molecules. The genotype LMLM produces M phenotype. the genotype LNLN gives the N phenotype. INdividauls of genotype LMLN have both kinds of molecules on their red blood cells, and their phenotype is MN.
codominance
if a red shorthorn cow is mated with a white bull, all their osffspring are roan, a phenotype that has a mixture of red and white hairs
co dominance
independnet genes at four different loci are responsible for determining an individual’s HLA tissue type, important in organ transplants and certain diseases
polygenic inhertiance
a recessive allele causes a human genetic disorder called phenylkeonuria. homozygous recessive individuals are unable to break down the amino acid phenylalanine. as a conseqquence, they have high levels of this substance in their blood and urine, reduced skin pigmentation, lighter hair than their normal brothers and sisters, and often some degree of mental impairment
pleiotrophy
when graphed, the number of individuals of various heights forms a bell-shaped curve
polygenic inhertiance
chickens homozygous for the black allele are black, and chickens homozygous for the white allele are white. heterozygous chickens are gray
incomplete dominance
most plants, including peas and corn (earthworms, and land snails too)
sexes not seperate; all individauls produce both eggs and sperm
humans and fruit flies
females are XX, males XY
date palms and marijuana
females are XX, males XY
some butterflies, birds, and fishes
females are ZW, males ZZ
grasshoppers and roaches
females are XX, males XO (one X)
