Vegetable People Practical

 

Year 10 Genetics Experiment- Vegetable People

Aim: To produce creative looking vegetable people based on the principles of probability and utilise Punnet squares with purpose.

Method:

1.    The genotypes we chose are outlined on the sheet.

2.    We used Punnet squares to work out the possible genotypes and phenotypes of the children.

3.    We tossed a thin eraser to pick the phenotypes of the vegetable children.

4.    After working everything out, the vegetable parents and child were made and photos were taken.

Discussion:

Eyes

Gender	S	S		S	S		S	p
S	SS	SS	p	Sp	Sp	p	Sp	pp
p	Sp	Sp	p	Sp	Sp	p	Sp	pp

SS+SS would result in 100% all babies being born with Sultana eyes. Sp+Sp would result in 75% having Sultana eyes. The other combinations are shown above in three different Punnet squares. Only the Sp+pp combination yields a 50% chance that the baby will be born with Pea eyes. The 25% chance of the Sp+Sp combination is low. Therefore, the most likely phenotype is the sultana eyes. Punnet squares used for the experiment are on the brief.

Arms

Gender	L	L		L	L		L	l
L	LL	LL	l	Ll	Ll	l	Ll	ll
l	Ll	Ll	l	Ll	Ll	l	Ll	ll

LL+LL would resultin 100% all babies being born with Sultana eyes. Ll+Ll would result in 75% having long arms. The other combinations are shown above in three different Punnet squares. The most likely phenotype is the long arms. This is due to it being the dominant phenotype.

Feet

Gender	C	C		C	b		C	C
b	Cb	Cb	b	Cb	bb	C	CC	CC
b	Cb	Cb	b	Cb	bb	b	Cb	Cb

Out of the six different combinations (CC, CC; Cb,Cb; bb,bb; CC,Cb; CC,bb; Cb,bb), three have the chance of passing on the parsnip feet characteristic. The percentages for the recessive characteristics are 25%, 100% and 50% respectively. The percentages for the dominant characteristics from the leftover combinations are 100%, 100% and 100% respectively. From this we may easily recognise that the most likely phenotypes are those which are related to the dominant genotypes.

Hair

The most likely phenotype for the hair is carrot shavings. There are two genotypes to code for the carrot shavings as it is a dominant characteristic. Celery leaves are recessive, with a much lesser chance of being inherited.

It was due to the flip of the coin. The ratio of male/female is close to 1:1. Most living things with a clear differentiation of gender have this ratio. There are four different combinations with the female being XX (homozygous) and the male being XY (heterozygous). The ratio is 1:1 only when the fertilisation rate of the X and Y is equal. The gender of most mammals are determined by the SRY gene which is on the Y chromosome. Those that are passed on this gene become males and those that don’t become females.The SRY gene codes for a protein called TDF. Other genes and hormones are required for the goal of the TDF to be achieved.

The chance ofthe vegetable child being both an onion and having pea eyes is 0%. This is due to the probability of the eye type being 100% for sultana eyes. There is no chance of the baby having pea eyes. The baby has a (near) 50% chance of being male or female. Basically it is 50%×0%=0%.

The practical was useful as it gave us the chance to practice filling in Punnet squares and understand the role of probability in the process of creating a vegetable child (and the genotypes of the parents.) I noticed that the mother, father and child looked similar, apart from the onion. All three vegetable people had sultana eyes. That genotype was heterozygous. If the child were to have vegetable children in the future, there may be a chance that the offspring has pea eyes. We did not have a coin and therefore used an eraser labelled with H and T. This may have been biased.

Conclusion:As well as reviewing and reinforcing our concepts and theory learned so far, this experiment shows that inherited characteristics appear in predictable ratios in the offspring.