Hardy-weinberg equation :D

January 9, 2007 at 8:50 pm #6721

Participant

hey!
i have 2 questions.

1. In a certain population, the dominant phenotype of a certain trait occurs 91% of the time. What is the frequency of the dominant allele?

i got 0.7 or 70%…
it’s either that or 0.91
i’m not sure.
which one do u think it is?

2. The allele for the hair pattern called widows peak is dominant over the allele for no widow’s peak. In a population of 1000 individuals, 510 show the dominant phenotype. How many individuals would you expect of each of the possible three genotypes for this trait?

Okay so i got
homozygous dominant 90
heterozygous 420
homozygous recessive 490

it’s that.. or…

510, 410, 80 (respectively)

can someone please check my answers… and check which ones are right?

thank you so much! i appreciate it greatly 🙂

Here are some of hte equations
p + q = 1
p^2 + 2pq + q^2

January 9, 2007 at 8:59 pm #65348

MrMistery

Participant

1. it’s 0.7. i can explain if you want
2. P-dominant; p-recessive
PP-90
Pp-420
pp-490

I can also explain. It is easy. Or do you understand?

January 9, 2007 at 9:02 pm #65350

sweetxd

Participant

thanks! yeah i understand… i just got confused at first. when they say dominant – that includes heterozygotes too.
i just wanted to make sure my answers were correct. thank you again! 🙂

January 9, 2007 at 9:17 pm #65353

MrMistery

Participant

hey no prob, i like to see people that actually do the work by themselves 😆

January 9, 2007 at 9:33 pm #65356

sweetxd

Participant

lol yeah

one more thing,

if
AA – 6
Aa – 9
aa – 0
———
15

then how do u find p and q.
because… since the recessive is 0.. there shoudl still be a q. but if u find the square root of 0 it’ll be 0. but there should still be q in the heterozygotes. so q can’t be = to 0… the recessive allele should never completely be removed bc of the heterozygotes… can someone clarify i’m confused 😥

would u do 9/15 = 0.6 / 2 = 0.3/ 0.4 = 0.75?.. ahah i.. idk

January 9, 2007 at 11:18 pm #65361

mith

Participant

9/30?

January 9, 2007 at 11:48 pm #65364

sweetxd

Participant

ohh.. is that for p or q? lol thanks

January 10, 2007 at 3:08 pm #65514

MrMistery

Participant

that does not follow Hardy Weinberg

January 12, 2007 at 8:59 am #65925

sdekivit

Participant

quote sweetxd:

lol yeah

one more thing,

if
AA – 6
Aa – 9
aa – 0
———
15

now p and q are allel frequencies, thus theallele frequency q vcomes from the heterozygous individuals 9/30 as already said

January 12, 2007 at 1:22 pm #65979

MrMistery

Participant

hey sdekivit. haven’t seen you around for some time..

January 13, 2007 at 7:28 pm #66403

sdekivit

Participant

quote MrMistery:

hey sdekivit. haven’t seen you around for some time..

true –> was very,very busy studying the mechanisms of metabolic regulation the past 7 weeks. It was very annoying to get it all in my brains 🙄 😆

January 13, 2007 at 7:38 pm #66404

Oscerot

Participant

Wow.

I just learned this yesterday in my grade 12 Academic Biology class. 😆 Got a bunch of questions to go along with it. 😆

January 15, 2007 at 4:48 pm #66726

Oscerot

Participant

Okay I have a question. I have a "snow day" today, so I thought I’d finish up my biology homework. Here’s a question;

quote :

Twenty-one percent of a population is homozygous dominant, 50 percent is heterozygous, and 29 percent is recessive. What percentage of the next generation is predicted to be recessive. Explain

So here are the variables I got;

p^2 = 0.21
q^2 = 0.29
2pg = 0.50

So now I am lost as to how to get the second generation. Help?

January 15, 2007 at 9:11 pm #66756

MrMistery

Participant

well it depends on the way the species reproduces: sexually, asexually.

Generally, if the species is in HW equilibrium(which never happens) the next generation will have the same gene percentages. so the answer should be 29%

January 15, 2007 at 9:41 pm #66761

Oscerot

Participant

I thought so too. There isn’t enough information given so I at first assumed that it must be in equillibrium.

Here’s another one;

quote :

The allele for a hitchikers thumb is dominant over a straight thumb. In a pop. of 1,000 people, 510 show the dominant phenotype. How many individuals would you expect for each of the three possible genotypes for this trait?

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