
QuestionĬomplete this Punnett square to show the allele combinations of the possible offspring produced. The straight coat allele is dominant (D) and the curly coat allele is recessive(d). The ratio of grey to white fur is 3:1 Question 1Ĭoat type in dogs is determined by a single gene with two alleles. The Punnett square is a visual representation of Mendelian inheritance. There is a 75% probability that the offspring will have grey fur.

The grey and the white are known as 'offspring phenotypes'. The genotype aa results in the phenotype white. The genotypes AA and Aa both result in the grey fur phenotype. In this Punnett square the top row shows the alleles of parent 1 and the left-hand column shows the alleles of parent 2. Determine the probability that the offspring will have grey fur. Two mice that are heterozygous for the fur colour gene mate. The inheritance of fur colour in mice is controlled by a single gene. You may be asked to comment on the proportion of different allele combinations in the offspring, calculate a probability, ratio or just determine the phenotypes of the offspring. Work out the new possible genetic combinations inside the Punnett square.The genetic experiments Mendel did with pea.

If an individual pea plant with the alleles T and t ( T tallness, t shortness) is the same height as a TT individual, the T allele (and the trait of tallness) is said to be completely dominant. 3) The Law of Dominance: An organism with alternate forms of a gene will express the form that is dominant.

If a parent has a dominant allele, the genotype is Dd or DD. If a parent has a recessive allele, the genotype, or scientific notation of the allele, is dd. As you can see, there are four possible results. dominance, in genetics, greater influence by one of a pair of genes ( alleles) that affect the same inherited character. To create a Punnett square, parents determine whether they have the dominant allele ( D) or the recessive allele ( d) of a visible trait. Split the alleles for each parent and add them into your Punnett square around the edges. The Punnett square illustrates the possible combinations of alleles that will occur in the offspring.You can use any letter you like but select one that has a clearly different lower case, for example: Aa, Bb, Dd. Explain how Mendels principles apply to all organisms.Lesson SummaryProbability and Punnett SquaresProbabilityis the likelihood that a particular event.
