Please enable JavaScript.
Coggle requires JavaScript to display documents.
Genetics (Ch 14–15) - Coggle Diagram
Genetics (Ch 14–15)
Mendel & B
asic Terms
Character
heritable feature
example: flower color
Trait
version of character
example: purple or white
Gene
unit of heredity (DNA segment)
Alleles
different versions of a gene
example: P vs p
Genotype
genetic makeup
example: PP, Pp
Homozygous
same alleles
example: PP or pp
Phenotype
physical appearance
example: purple flowers
Heterozygous
different alleles
example: Pp
Complex Genetics
Incomplete Dominance
blend phenotype
example: red + white = pink
Codominance
both show
example: AB blood type
Multiple Alleles
more than 2 alleles
example: IA, IB, i
Polygenic Inheritance
many genes affect trait
example: height, skin color
Epistasis
one gene affects another
example: lab coat color
Crosses
Monohybrid Cross
one trait
example: Pp × Pp
Dihybrid Cross
two traits
example: AaBb × AaBb
Punnett Square
predicts offspring outcomes
3:1 Ratio
dominant : recessive phenotype
Human Genetics
Pedigree
family tree showing inheritance
Carrier
has allele but no symptoms
Recessive Disorders
need 2 alleles
examples: cystic fibrosis, sickle cel
Dominant Disorders
need 1 allele
example: achondroplasia
Linked Genes
Linked Genes
on same chromosome
inherited together
Crossing Over
exchange DNA
creates variation
Recombinant
new trait combo
Chromosome Errors
Nondisjunction
chromosomes don’t separate
Aneuploidy
wrong number of chromosomes
Trisomy
extra chromosome
example: Down syndrome
Monosomy
missing chromosome
example: Turner syndrome
Sex-Linked Traits
X-linked
gene on X chromosome
Why males affected more
only one X
Examples
color blindness
hemophilia
Dominance
Dominant
shows if present
example: P (purple)
Recessive
hidden unless 2 copies
example: p (white)
Mendel’s Laws
Law of Segregation
alleles separate in gametes
each gamete gets ONE allele
happens in meiosis
Law of Independent Assortment
genes separate independently
only if on different chromosomes
Probability
Multiplication Rule
both events happen
example: ½ × ½ = ¼
Addition Rule
either event happens
add probabilities
Chromosome Theory
Chromosome Theory
genes located on chromosomes
Morgan Experiment
fruit flies
proved genes on X chromosome
