Jonas B. Pira                                                            Mr.Orlie Orbita

            II-Mendel                                                                     Biology

Monohybrid

1.    In summer squash, white fruit color (W) is dominant over yellow fruit color (w).  If a squash plant heterozygous for white is crossed with a plant homozygous for yellow, what will the phenotypic and genotypic ratios?

 

2.    If in pea plants, G=green pods and g = yellow pods, what would be the genotypic and phenotypic ratio of the yellow pea plant cross to heterozygous green plant?

 

3.    If in pea plants T=tall and t=short, what would be the genotype and phenotype and ratio if a homozygous tall plant cross with short plant?

 

Dihybrid

1.    In summer squash, white fruit color (W) is dominant over yellow fruit color (w) and disk-shaped fruit (D) is dominant over sphere-shaped fruit (d).  If a squash plant true-breeding for white, disk-shaped fruit is crossed with a plant true-breeding for yellow, sphere-shaped fruit, what will the phenotype and genotype?

 

2.    In rat the gene for coat color has two forms.  The allele for colored coat (C) is dominant to the allele for albino(c).  There are two forms for the gene controlling whiskers, as well, straight (S) is dominant to bent(s). What will be the phenotypic and genotypic ratios of the offspring if an albino with straight whiskers rat unite with colored coat and also with straight whiskers rat?

 

3.    In fruit flies, normal wings(N) are dominant to vestigial wings(n) and gray bodies(C) are dominant to black bodies(c). What will be the phenotypic and genotypic ratios of the offspring if a normal wings with gray body flies combine with normal wings and with black body flies?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Answer:                                

Monohybrid                                                                                    Dihybrid

1.WW= white,

 ww= yellow

	W	w
w	Ww	ww
w	Ww	ww

 

 

 

 

GR= 1 Ww : 1ww

PR=     1 white : 1 yellow

2. gg= yellow pea plant,  

Gg= heterozygous green plant

	G	g
g	Gg	gg
g	Gg	gg

 

 

 

 

GR= 1 Gg : 1 gg

PR= 1green : 1 yellow                                               

 

3. TT= heterozygous tall plant,

  tt=short plant

	T	t
t	Tt	tt
t	Tt	tt

 

 

 

Genotype- 1 Tt , 3tt            

 Phenotype- 1 tall plant ,3 short

GR= 1Tt : 3 tt           PR= 1 tall : 3 short

 

 

 

 

 

 

 

 

 

 

1. 1^st plant - WWDD – WD WD WD WD,

2^nd plant-  wwdd – wd wd wd wd               

	WD	WD	WD	WD
wd	WwDd	WwDd	WwDd	WwDd
wd	WwDd	WwDd	WwDd	WwDd
wd	WwDd	WwDd	WwDd	WwDd
wd	WwDd	WwDd	WwDd	WwDd

Genotype=16 WwDd

Phenotype=16 white disk shapes fruit

2. 1^st rat- ccSs- cS cs cS cs

    2^nd rat-CcSS-CS CS cS cS

	cS	cs	cS	cs
CS	CcSS	CcSs	CcSS	CcSs
CS	CcSS	CcSs	CcSS	CcSs
cS	ccSS	ccSs	ccSS	ccSs
cS	ccSS	ccSs	ccSS	ccSs

GR=1 CcSS : 1CcSs : 1ccSS: 1ccSs

PR=1 colored, straight: 1 albino, straight

3.1^st  fly-NnCc- NC Nc nC nc

   2^nd  fly-NNcc-Nc Nc Nc Nc

	NC	Nc	nC	nc
Nc	NNCc	NNcc	NnCc	Nncc
Nc	NNCc	NNcc	NnCc	Nncc
Nc	NNCc	NNcc	NnCc	Nncc
Nc	NNCc	NNcc	NnCc	Nncc

GR= 1NNCc : 1NNcc : 1NnCc : 1Nncc

PR=2normal,gray: 2normal,black