Please enable JavaScript.
Coggle requires JavaScript to display documents.
Mendel & the gene idea - Coggle Diagram
Mendel & the gene idea
Quantitative approach
Mendel's approach to study heredity
trait-specific character trait ex- black hair
character-the general trait ex-hair color
true breeding-plants self-pollinate to produce same variety of offspring
P1 generation- true breeding parents
F1 generation- offspring of the parent generation
F2 generation- offspring of the F1 generation
allele-alternate version of a gene
dominant-determines allele shown
recessive-no noticeable affect on appearance
law of segregation- alleles separate during anaphase 1 & 2 and end up in different gametes
punnette square & test cross
test cross-breeding the individual with a homozygous recessive one
punnett square- shows possible offsrping
heterozygous-two different alleles
phenotype & genotype
genotype- genetic makeup
phenotype-what is shown in appearance
homozygous-two identical alleles
law of independent assortment
occurs during metaphase 1
dihybrid- different traits crossed creating dihybrid cross
monohybrid-only 1 (heterozygous offspring) which is known as monohybrid cross
alleles segregate alone randomly
mendelian patterns/inheritance
pedigree-family tree showing inheritance of genes throughout generations
recessive alleles
carriers-heterozygous individuals who carry a recessive allele but phenotypically normal
diseases
sickle cell- substitution of a single amino acid in the hemoglobin protein in red blood cells
Huntington's disease- degenerative disease of the nervous system
cystic fibrosis- defective chloride transport channel leading to buildup of chloride out of cell
fetal testing
chrorionic villus sampling (CVS)-sampled of placenta is removed and tested
amniocentesis-liquid that bathes the fetus is removed and tested for genetic disorders
chromosome theory of inheritance- specific gene with specific chromosome
sex-linked genes and more
gene located on either sex chromosome
x-linked genes- gene on the x chromosome
examples: color blindness,homophillia,duchenne muscular dystrophy
linked genes-genes located on the same chromosome tend to be inherited together
genetic recombination-production of offspring with combination of traits differing from either parent
parental types- offspring with phenotype matching one of the parental (P) phenotypes
recombinant types- offspring with nonparental phenotypes
crossing over
genetic map- ordered list of the genetic loci along a particular chromosome
map units-distance between genes
linkage map-genetic map of chromosomes based on recombination frequencies
Probability & inheritance
inheritance
codominance-two different alleles affect the phenotype in separate ways
complete dominance- phenotypes identical between heterozygote & homozygote
incomplete dominance- blending of traits
Tay-Sachs disease- fatal inherited disorder; dysfunctional enzyme causes accumulation of lipids in the brain
Polygenic inheritance-
,is an additive effect of two or more genes in a phenotype
quantitative characters-those that vary in population along a continuum
probability
addition rule-probability of one of two or more mutually exclusive events occur is calculated by adding their individual probabilities
multiplication rule- probability two or more individual events will occur together = product of their individual probabilities
pleiotropy-most genes have multiple phenotypic effects
epistasis-one gene affects many genes
multifactorial-traits depend on multiple genes combined with environmental influences
genetic disorders
nondisjunction- pair of homologous chromosomes do not separate normally during meiosis
aneuploidy-have an abnormal number of a particular chromosome
trisomic-zygote with three copies of a particular chromosome
monosomic-zygote only has one copy of a particular chromosomes
polyploidy-condition in which an organism has more than two complete sets of chromosomes
change in chromosome structure
deletion removes a chromosomal fragment
duplication repeats a segment
inversion reverses orientation of a segment within a chromosome
translation moves a segment from one chromosome to another
down syndrome-aneuploid condition that results from 3 copies of chromosome set 21
genomic imprinting
phenotype depends on which parent passed an allele for those traits