Transcript Rat Genetics

Rat Genetics
Male Rat (Dad)
• Phenotype
– Black Hair
• Genotype
– BB / Bb
Female Rat (Mom)
• Phenotype
– Gray (shade of
Black) Hair Coat
• Genotype
– BB / Bb
Vocabulary Terms
• Heterozygous: The 2 alleles for the
trait are different ex. Bb 1
dominate & 1 recessive
• Homozygous: The 2 alleles for the
trait are the same ex. BB or bb 2
dominant or 2 recessive
• Phenotype: Physical appearance
• Genotype: Genetic traits (BB /Bb / bb)
What will their offspring’s phenotype and
genotype be if female is heterozygous
dominant for black hair and the male is
homozygous for black hair?
• Female Male
– Bb
-BB
• Offspring
•
•
•
•
Black Hair
White Hair
Homozygous
Heterozygous
st
1
Mating Offspring / F1
Generartion (babies)
• 9 lived
• Phenotype
– 100% Black Hair
Coat
• Genotype
– 100% BB / Bb
What will their offspring’s phenotype
and genotype be if male and female is
heterozygous dominant for black hair?
• Female Male
– Bb
-Bb
• Offspring
•
•
•
•
•
Black Hair
White Hair
Homozygous
Dom. Rec.
Heterozygous
2nd Mating / F2 Generation
Offspring
• phenotype
– 75% Black Hair Coat
– 25% White Hair Coat
• Genotype
– 75% BB / Bb
– 25% bb
So based on the phenotypes of the
second mating offspring we now
know….
• Both Female (mom) and Male
(dad) genotype has to be..
–Bb Heterozygous Dominant
for black hair
Your Turn:
Name: ___________ Per___
What would happen if you breed the white
homozygous (bb) rat to an black homozygous rat
(BB)?
• Phenotype
black ________%
white ________ %
• Genotype
• ___ ______%
• ___ ______%
• Draw/Color picture to show
Phenotype of offspring on back of
this sheet