What is a gene?
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Not that kind of jeans!
A second pair of genes!
Oh my FAMILY
TREE
Dominant?
Or maybe not
What will they inherit?
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What is a gene?
Answer
• Segment of DNA that codes for a specific trait
An individual who has two different
alleles for a gene is _____________ .
Answer
• HETEROZYGOUS
If an allele does not affect the phenotype
of a heterozygous individual, the allele
is _________ .
Answer
• recessive
A striped fruit fly is crossed with a non-striped fly. N = non-striped is dominant n = striped is recessiveWhat is the genotype of the striped parent?
Answer
• nn
A striped fruit fly is crossed with a non-striped fly. All 100 offspring are non-striped.
N = non-striped is dominant n = striped is recessive
What is the genotype of the non-striped parent?
Answer
• NN
What is an allele?
Answer
• A form of a trait located at a gene. ( gene for blue eyes vs gene for brown eyes)
An individual who has two identical
alleles for a gene is __________ .
Answer
• homozygous
What does it mean if an allele
is dominant?
Answer
• It prevents (covers up) the other allele (recessive) from being expressed.
The ‘B’ gene controls the color of a dog’s coat. The ‘R’ gene controls the texture.Which alleles, B, b, R, and/or r, would occur in all the offspring of the following parents?
BbRR x bbRr
Answer
• R would be in each offspring
• b would also be in each offspring
The ‘B’ gene controls the color of a dog’s coat. The ‘R’ gene controls the texture.
Which trait would occur in all the offspring of the following parents?
bbRR x BbRr
Gene Dominant Recessive
Color B=Black b=White
Texture R=Rough r=Smooth
Answer
• ROUGH
What types of PEDIGREE is this?
Answer
• Autosomal dominant
What types of PEDIGREE is this?
Answer
• Autosomal recessive
What types of PEDIGREE is this?
Answer
• X-linked recessive
What types of PEDIGREE is this?
Answer
• X- linked dominant
The law of independent assortment describes the inheritance of genes on different chromosomes and the behavior of chromosomes at the beginning ofa. meiosis 1b. meiosis 2c. mitosisd. all of the above.
Answer
• Meiosis I
In a heterozygous individual, the
______________ allele determines the
phenotype.
Answer
If a heterozygous individual has a phenotype that is
intermediate between both types of homozygous
individual, the two alleles show _______ _______.
Answer
• Incomplete dominance
Type AB blood is an example of
______________.
Answer
• 2 co-dominant Alleles
• Both A and B are expressed
A child has a genetic disease caused by a single
gene. Neither parent has the disease. The allele that
causes the genetic disease is __________ .
Answer
An allele of a single gene causes a disease that affects many more males than females. This allele is
a. autosomal dominantb. autosomal recessivec. X-linked dominantd. X-linked recessive
Answer
• X-linked recessive
A daughter inheritsa. more genes from her motherb. more genes from her fatherc. one copy of each gene from her mother and one copy from her father
Answer
• C- duh
A man who is heterozygous for the albino allele is married to a woman who is homozygous for normal skin color (Aa x AA). What fraction of their children would you expect to be albino?
Answer
• O %
If a son has an X-linked condition (e.g. color blindness or hemophilia), he must have inherited the gene for this condition from his ________.
Answer
• momma
A mother has type O blood and her husband has type AB blood. What blood types can their children have?
Answer
• AO = type A
• BO = type B
• AB = type AB
• Oo = type o
Parents who are both heterozygous for the alleles for albinism (Aa x Aa) have 2 heterozygous children. Now, the mother is expecting fraternal twins. The most likely genotypes for these twins are ___ and ___.
Answer
• Heterozygous and heterozygous