So the mother could be ‘Aa’ or ‘AA’. Hope what's there helps anyway.. :)I do actually have more notes than is posted, and these can be purchased by buying my IGCSE Notes sets. The affected child is aa and the unaffected child can either be Aa or AA.The father is affected, so he has genotype aa. E.g. It is ‘a’ that codes for albinism, making albinism a recessive disorder.At the top of the chart, in the first generation, both male and female are unaffected, so they could be AA or Aa.When we look at the next generation, we can see that there are both affected and unaffected offspring. I hope what I had time to post back during IGCSEs helps anyway!! Key vocabulary is highlighted throughout.

Albinism results in white patches are completely white skin, and sometimes pale blue or pale pink irises. We cannot, however, deduce the mother’s genotype from the given information.In a similar fashion, we can work out the genotypes for the final family.If you have any queries, complaints or suggestions, feel free to comment, or write to us at:The IGCSE AID Team is based in the little state of Kerala in South India.

I hope you find this useful!
IGCSE AID. Our online Biology GCSE catchup courses on 24-25 August will review Year 10 content, getting you ready for September. However, the child has a father that is homozygous recessive, so she must have inherited at least one ‘a’ allele from her father, meaning that we can deduct that the child’s genotype is Aa. Sorry, your blog cannot share posts by email. Start studying 17.5 Monohybrid Inheritance (IGCSE Biology 0610). Learn vocabulary, terms, and more with flashcards, games, and other study tools. Inheritance Revision Notes.

If you spot any mistakes, please let me know, thank you! t.You should also know that in some diagrams, they use the terms FBefore I get to the monohybrid cross diagrams, let me show you what a Punnett grid is:We use these to help us calculate all the possible offspring genotypes and the likelihood of each genotype being born.Note that in diploid organisms, one set of chromosomes contain one of the alleles for a particular trait, and the other set of chromosomes will get the other allele.As a result, all the offspring genotypes are Aa (heterozygous).Since A is the dominant allele, all offspring will display the phenotype resulting from A.The allele A codes for normal and the allele a codes for albinism (a condition in which the body cannot produce the pigment melanin – which is what gives skin its brownish colour. :)Btw, I did take information out of textbooks.

Their genotypes are aa.The other offspring are white, and so unaffected. This PowerPoint explains monohybrid inheritance with a few examples and punnet squares. Note that this cross results in a 3 : 1 phenotypic ratio:When you cross them, the results are one homozygous dominant offspring (normal), two heterozygous offspring (also normal) and one homozygous recessive organism (albino).This means the ratio of phenotypes normal : albino is 3 : 1.So, there is a ¾ chance of the cross resulting in a normal offspring if only one child is born, and a ¼ chance of an albino offspring if one child is born.The last cross we should look at is a cross involving a 1 : 1 ratio:Note that this happens when one of the parents are heterozygous and the other parent homozygous recessive.A pedigree chart or diagram is a diagram that shows the occurrence and appearance of phenotypes of a particular gene from one generation to the next.Say that the gene we are looking at is the gene for albinism. It would be great if you can tick a box at the bottom of each post to show me what you think, and please feel free to leave comments! ... Use genetic diagrams to predict the results of monohybrid crosses and calculate phenotypic ratios, limited to 1:1 and 3:1 ratios; I’ll explain this learning objective together with the next one because they’re heavily related. These have been made according to the specification and cover all the relevant topics in the syllabus for examination in May/June as well as October/November and March. I have tried to make it as appealing lots of colours, images and animations. As a rule, monohybrid crossing is used to determine what the second generation will be from a couple of parents. If you are interested in buying scanned PDF copies of my handwritten HL Bio notes, please find the links below. Notes for the CIE IGCSE Biology topic: 17. The recessive version would generally be written as ‘a’. )A is dominant, so wherever A is present, the organism will be normal.This means one of the parents is normal and the other an albino, and all the offspring are normal.Here’s a cross between two F1 organisms.
A genetic diagram consists of the parents gamets (according to their genotype) and their possible offspring: (B and b represent an allele for a gene) Clicking on the links simple redirect you to a description of the notes + a preview. There are three offspring.

If one of them was AA, and the other Aa, the children would either be AA or Aa, so none of them would be affected. 17.

B11.3 – Monohybrid Inheritance. Written explanations are as simple as possible as a lot of my pupils are EAL learners. Start studying IGCSE Edexcel Biology - Monohybrid Inheritance. Monohybrid Cross Definition “A monohybrid cross is the hybrid of two individuals with homozygous genotypes which result in the opposite phenotype for a certain genetic trait.” “The cross between two monohybrid traits (TT and tt) is called a Monohybrid Cross.” Monohybrid cross is responsible for the inheritance of one gene. The child is also unaffected so she could be AA or Aa.