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Genetics - Teachers MindMap - Coggle Diagram
Genetics - Teachers MindMap
ALLELE
a form of a gene
heterozygous (different)
homozygous (same)
MONOHYBRID CROSS
1 trait
homozygous dominant X homozygous recessive
ALL OFFSPRING HAVE DOMINANT TRAIT
heterozygous X homozygous recessive
1:1
heterozygous X heterozygous
3:1
3 = dominant
1 = recessive
DIHYBRID CROSS
2 traits
homozygous dominant for both X homozygous recessive
ALL OFFSPRING HAVE DOMINANT TRAITS
heterozygous X homozygous recessive
1:1:1:1
OFFSPRING DIFFERENT TO PARENTS = INDEPENDANT ASSORTMENT
heterozygous X heterozygous
9:3:3:1
LINKED GENES
on the same chromosome and are inherited together
look for homozygous parent
no independent assortment
no variation
all children like parents
SEX LINKED
normal is dominant
genes found on
X
chromosome
males have
XY
chromosomes
gets
X
from mother
they have 1 gene for these diseases
females have 2
X
's (
XX
)
1 from each parent
they have 2 genes for these diseases
Example:
haemophilia, red-green colour blindness
males are more likely to be sufferers as males need 1 recessive gene while females need 2
INCOMPLETE DOMINANCE
neither gene is dominant or recessive
there is an intermediate (middle) phenotype
Example:
red + green = pink