Module 4 - The Principle of Genetics Flashcards
idea that genetic material from 2 parents blend together (ex. blue and yellow paint make green)
blending hypothesis
idea that parents pass on discrete heritable units (genes)
particulate hypothesis
heritable feature that varies among individuals
character
each variant for a character, such as purple or white for flowers
trait
Mendel mated 2 contrasting, true-breeding varieties
hybridization
true-breeding parents
P generation
hybrid offspring of the P generation (hybrids)
F1 generation
produced when F1 individuals self-pollinate or cross-pollinate with other F1 hybrids
F2 generation
what Mendel called a “heritable factor” is what we now called a
gene
used to show possible combinations of sperm and egg
punnet square
organism with two identical alleles for a character
homozygous
organism that has 2 different alleles for the gene controlling that character
heterozygous
T/F- an organism’s traits do not always reveal its genetic composition due to the different effects of dominant and recessive alleles
true
refers to the physical appearance
phenotype
refers to the genetic makeup
genotype
a cross between heterozygotes following one character
monohybrid cross
describes the segregation of alleles from different genes into gametes
law of independent assortment
cross between F1 dihybrids
dihybrid cross
describes the segregation of alleles within one gene into gametes
law of segregation
occurs when phenotypes of the heterozygote and dominant homozygote are identical (dominant allele completely masks the recessive one)
complete dominance
the phenotype of F1 hybrids is somewhere between the phenotypes of the 2 parental varieties (neither allele is dominant)
incomplete dominance
two dominant alleles affect the phenotype in separate, distinguishable ways (both alleles are dominant)
codominance
T/F - dominant alleles are more common in populations than recessive ones
false
a property where most genes have multiple phenotypic effects
pleiotropy
occurs when a gene at one locus alters the phenotypic expression of a gene at a second locus
epistasis
an addictive effect of two or more genes on a single phenotype
polygenic inheritance
T/F - many human traits follow Mendelian patterns of inheritance
true
a family tree that describes the interrelationships of parents and children across generations
pedigree
are heterozygous individuals who carry the recessive allele but are phenotypically normal
carriers
a recessive condition characterized by a lack of pigmentation in skin and hair
albinism
T/F - dominant alleles that cause a lethal disease are rare and arise by mutation
true
a form of dwarfism caused by a rare dominant allele
archondroplasia
a gene that is located on either sex chromosome is called a
sex-linked gene
T/F - x-linked recessive disorders are much more common in females than in males
false
genes located on the same chromosome that tend to be inherited together
linked genes
offspring with a phenotype matching one of the parental phenotypes
parental types
offspring with non parental phenotypes (nee combination of traits)
recombinant types/ recombinants
T/F - higher than 50% frequency of parental types means that the genes are linked
true
results from the fertilization of gametes in which nondisjunction occured
aneuploidy
a breakage of chromosome can lead to 4 types of changes in chromosome structure
- deletion
- duplication
- inversion
- translocation
an aneuploid condition that results from 3 copies of chromosome 21
down syndrome (trisomy 21)
result of an extra chromosome in male, producing XXY individuals
klinefelter syndrome
produces X0 females who are sterile; only known viable monosomy in humans
monosomy X (turner syndrome)
results from a specific deletion in chromosome 5
cri du chat (“cry of the cat”)
cancers that are caused by translocations of chromosomes
chronic myelogenous leukemia (CML)
