In humans, normal skin pigmentation is governed by a dominant allele (), while albinism is caused by a recessive allele (). Match each parental cross combination on the left with its corresponding expected offspring phenotypic and genotypic outcome on the right according to Mendel's First Law.
- Heterozygous normal individual () Heterozygous normal individual () ratio of normal pigmentation to albino offspring ()
- Homozygous normal individual () Albino individual () normal pigmentation, with all offspring being heterozygous carriers ()
- Heterozygous normal individual () Albino individual () ratio of normal pigmentation to albino offspring ()
- Homozygous normal individual () Heterozygous normal individual () normal pigmentation, with a genotypic ratio of non-carriers () to carriers ()
Answer
The parental crosses match their expected offspring outcomes as follows: produces a phenotypic ratio of normal to albino offspring; produces normal heterozygous carriers (); produces a ratio of normal to albino offspring; and produces normal offspring with a ratio of non-carriers () to carriers ().
Each parental cross follows Mendel's Law of Segregation. A cross between two heterozygotes () yields a 3:1 phenotypic ratio (3 normal : 1 albino). A cross between homozygous dominant and homozygous recessive () produces 100% normal carriers (). A back/test cross () yields a 1:1 ratio of normal to albino. A cross between homozygous dominant and heterozygous () produces 100% normal offspring, split equally between non-carriers () and carriers ().
Step-by-Step Solution
Key Concept
Mendel's First Law and Monohybrid Cross Inheritance Ratios
Estimated Time:1m 30s