GENETICS & INHERITANCE
HEREDITARY - tendency for the characteristics of parents to be passed to
their offspring
LOCUS - the position of gene on a chromosome
ALLELE - two or more alternative forms of a gene at the same locus on
homologous chromosomes
Homozygous recessive
Homozygous dominant
Allele’s are the same
Allele’s are the same
bb
BB -> genotype
Allele’s of a
chromosome
Heterozygous
Allele’s are different
Bb
Genotype:
: alleles for characteristics
: BB, Bb, bb
, Phenotype:
: description of the condition produced by the alleles
: brown hair
DOMINANT ALLELE RECESSIVE ALLELE
Shows in the phenotype when Not shown in the phenotype
in heterozygous or when in heterozygous
homozygous condition condition
Capital letter Both alleles must be recessive
for recessive gene to show
Lowercase letter
Examples:
B - brown hair
b - blond hair
BB Bb bb
Homozygous dominant Heterozygous Homozygous recessive
Brown hair Brown hair Blond hair
MENDEL - THE FATHER OF GENETICS
GREGOR MENDEL - made the first break through in understanding how
characteristics were inherited
*STUDIED MONOHYBRID INHERITANCE
HEREDITARY - tendency for the characteristics of parents to be passed to
their offspring
LOCUS - the position of gene on a chromosome
ALLELE - two or more alternative forms of a gene at the same locus on
homologous chromosomes
Homozygous recessive
Homozygous dominant
Allele’s are the same
Allele’s are the same
bb
BB -> genotype
Allele’s of a
chromosome
Heterozygous
Allele’s are different
Bb
Genotype:
: alleles for characteristics
: BB, Bb, bb
, Phenotype:
: description of the condition produced by the alleles
: brown hair
DOMINANT ALLELE RECESSIVE ALLELE
Shows in the phenotype when Not shown in the phenotype
in heterozygous or when in heterozygous
homozygous condition condition
Capital letter Both alleles must be recessive
for recessive gene to show
Lowercase letter
Examples:
B - brown hair
b - blond hair
BB Bb bb
Homozygous dominant Heterozygous Homozygous recessive
Brown hair Brown hair Blond hair
MENDEL - THE FATHER OF GENETICS
GREGOR MENDEL - made the first break through in understanding how
characteristics were inherited
*STUDIED MONOHYBRID INHERITANCE
