1. In a test cross for a tall (T) individual you should cross it with which geno
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Question
1. In a test cross for a tall (T) individual you should cross it with which genotype(s).
a) TT b) Tt c) tt d) Either TT or tt
2. In many species of flowering plants, the gene(s) responsible for flower color are incompletely dominant. A cross of a red rose and a blue rose will create what color(s) of flowers?
Red b) Blue c) Both red and blue d) Purple e) Red, Blue, and Purple
3. T is tall while t is short. Which individual genotype guarantees all tall offspring. EXPLAIN your answer.
4. Explain the the difference in the relationship between alleles for a trait governed by incomplete dominance versus one governed by co-dominance.
5. G is green while g is white. List the cross which will guarantee 50% of the progeny will be green and 50% will be white. EXPLAIN your answer.
Explanation / Answer
1.c.The organism in question is crossed with an organism that is homozygous for the recessive trait.Thus here tt is used .
2.e.red ,blue and purple flowers
3.TT selfed will guarantee all tall offsprings.Also if TT is crossed with Tt, it will also produce all tall offsprings in F1 generation.For eg. If a person has 2 dominant alleles for tallness: T T then he will be tall. If a person has 1 dominant and I recessive allele for tallness: T t then he will be tall. The only way the recessive gene will be expressed is if he has 2 recessive alleles for short: t t then he will be short.
4.In complete dominance, the effect of one allele in a heterozygous genotype completely masks the effect of the other. The allele that masks the other is said to be dominant to the latter, and the allele that is masked is said to be recessive to the former. Complete dominance therefore means that the phenotype of the heterozygote is indistinguishable from that of the dominant homozygote.For eg.The RR individuals have round peas and the rr individuals have wrinkled peas. In Rr individuals the R allele masks the presence of the r allele, so these individuals also have round peas. Thus, allele R is dominant to allele r, and allele r is recessive to allele R.
Incomplete dominance is a form of intermediate inheritance in which one allele for a specific trait is not completely expressed over its paired allele. For eg. Red and white flowers when crossed they produce pink flowers.
5.In f2 generation if Gg is crossed with Gg then only 25% will be white.
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