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A gene that affects hair length in dogs has two alleles. The allele for short hair (L) is dominant

to the allele for long hair (1). A cross of heterozygous two short-haired dogs produces six short-
haired and two long-haired offspring. Which of the following best explains how the long-hair
phenotype can appear in the offspring of two short-haired dogs?

User Favolas
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1 Answer

2 votes

Answer:

This question lacks options, the options are:

A. Only recessive alleles are inherited from homozygous parents.

B. Dominant alleles grow weaker as they are passed from parents to offspring.

C. Only the parent with a dominant allele can pass that allele to offspring in sexual reproduction.

D. A heterozygous parent has an equal chance of passing either the dominant allele or the recessive allele to offspring.

The answer is D

Step-by-step explanation:

This question involves a single gene coding for hair length in dogs. The allele for short hair (S) is dominant over the allele for long hair (s). This means that allele 'S' will always mask the phenotypic expression of allele 's' in a heterozygous state.

According to the question, two heterozygous dogs (Ss) were crossed to produce 6 shortt-haired offsprings and 2 long-haired offsprings. An heterozygous organism is that which contains two different alleles for a particular gene i.e. a combination of dominant and recessive alleles.

Based on this, during meiosis or gamete formation, an heterozygous dog (Ss) will produce gametes with the short hair allele (S) and long hair allele (s) in equal proportion i.e. 50-50. When the two gametes containing the recessive alleles (s) produced by each heterozygous parent fuses, an offspring with a recessive phenotype (long hair, ss) is produced.

Hence, a long-hair

phenotype can appear in the offspring of two short-haired dogs because a heterozygous parent has equal chance of passing either the dominant or recessive allele to the offspring.

User Vineesh TP
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