182Chapter 15Using the Punnett SquareThe Punnett Square is a simple method of predicting the probableoutcome of genetic crosses.Step 1Draw a square like this:Put the gametes ofone parent here.Putthe gametesof the otherparent here.Step 2Determine what kinds of gametes are made by each parent in the cross,and put those gametes into the boxes of the Punnett Square.If your mate isheterozygous(Ff), then thosegametes areFor example, if youare homozygousrecessive forattached earlobes(ff), then all of yourgametes areStep 3Fill in the offspring boxes of the Punnett Square.Why is itunnecessary to fillin this box withanother smallf?ffF FfIn this example there are only two possible offspring genotypes. ThePunnett Square tells us to expect about 50% ff and 50% Ff.Sometimes the Punnett Square is more complex than this and youmust figure out more than one trait at a time. Nevertheless, you use thesame basic method.ProcedureMake up your own genotype example and work out the crosses.1 Traits:2 Symbols:3 Male Genotype:4 Female Genotype:5 Offspring Genotypes:

Name: 182Chapter 15Using the Punnett SquareThe Punnett Square is a simple m
Uploaded: 2024-03-20T06:42:55.000Z
Channel: Bartleby
Description: 182Chapter 15Using the Punnett SquareThe Punnett Square is a simple method of predicting the probableoutcome of genetic crosses.Step 1Draw a square like this:Put the gametes ofone parent here.Putthe gametesof the otherparent here.Step 2Determine wha

The Punnett Square is a simple method of predicting the probable outcome of genetic crosses. If your mate is heterozygous( two different types of alleles for a gene), (Ff), then those gametes are F and f. For example, if you are homozygous recessive for attached earlobes. (ff), then all of your gametes are f. It is unnecessary to write another f because it is homozygous (the same types of alleles for a gene). Mendel's law of dominance: A recessive allele can show its characters in the phenotype only in a homozygous recessive state. Whereas a dominant allele can show its characters in offspring both in homozygous and heterozygous states. Procedure: Make up your genotype example and work out the crosses. 1. Traits: Height, Talleness is determined by a dominant allele, ( T) and its recessive form is 'to for short stature ( dwarfism). 2. Symbols: Tall (T), dwarf( t) 3. Male genotype: Tt ( Heterozygous Tall) 4. Female genotype: Tt ( heterozygous tall) 5. Offering genotype: TT, Tt, Tt, tPunnett Square Gametes T t T TT Homozygous dominant ( Tall) Tt Heterozygous tall t Tt Heterozygous tall tt Homozygous recessive ( dwarf)5. Offering genotype: TT, Tt, Tt, tt Genotype ratio: 1:2:1 Phenotype ratio; 3:1 (3 Tall: 1 dwarf)