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Introduction to Heredity

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2451 ratings | 1109573 views
Heredity and Classical Genetics. Dominant and recessive traits. Heterozygous and homozygous genotypes. More free lessons at: http://www.khanacademy.org/video?v=eEUvRrhmcxM
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Text Comments (328)
Audreey Cat (16 days ago)
Thanks ♥
27capricia (1 month ago)
Thank you so much. I have always been confused about this until now. I now get it.
Litsy Hernandez (2 months ago)
"Brown hot eye girl" lol so funny.
Harley Hatcher (3 months ago)
all of your school sucks my rocks
Yousoof Abd-kabir (3 months ago)
thank you so much.... I'm highly OK with it...
Tiffany Nguyen (3 months ago)
He beats around the bush wayyyy too much. This video could’ve been 9 minutes if he didn’t stall and stammer all the time.
Mitzey Sweetsong (4 months ago)
Been playing the RTS and Genetics Sim game Beetle Uprising on Steam - had to come here and refresh my genetics understanding so I could figure out the breeding - thanks for the gaming help!
ella mae castro (4 months ago)
how is the basic principles of genetics can be applied to human hereditary?
K. Azurin M. (4 months ago)
Let's say the father has blue eyes (both his parents have blue eyes too), and the mother has brown eyes (both her parents have brown eyes too). How does the probability work out for the child to get blue eyes?? Who of the father's and mother's genes become the dominant and the recessive?? Like how do you figure who is dominant and recessive??
Kevin Yang (4 months ago)
Lol messin around with plants
The BABA (4 months ago)
But dude how does a trait claims dominance? you know in humans we fight but i dont suppose these traits do that too?
MustWatch Live (5 months ago)
Hey if u go to prep like my comment
Christiana Kerns (6 months ago)
quiz today thanks for your help
Mr. Tangerine (7 months ago)
I had to do this for my science "Choose your own 'adventure' (Assignment)" project, but, I developed a liking to your videos
Om Shiv Sharma (7 months ago)
how can i download this videos in pc
Dave Buikema (7 months ago)
brown eyed girl looks like coraline lmao
Kyle St. Louis (8 months ago)
Hey you! my brown eyed girl! van Morrison is gonna be pissed!
Deeni Channel (8 months ago)
Can u convert it into hindi
Ara Angela Saluan (8 months ago)
Exams tomorrow and I left my notebook in school *facepalm*
Madhusmita mallia (8 months ago)
Could you tell about interference and coincidence in genetics??
Erick Ajt (8 months ago)
Дороу
YouTube Profile (9 months ago)
Hilarious drawings.
Raenette Butterfield (9 months ago)
this was so simple to understand . thank you for the examples. I learned this about 2 years ago but I did not grasp the information as easy as I just did from watching this video. thank you again!!
Caughtlighght (10 months ago)
This is a great vid Sal
Ape Man (1 year ago)
Really Helpful For grade 9 Science Pray for Canada
becomingBRITTANY (1 year ago)
Here in 2017 with a test tomorrow, thanks!!!
Sanjeev Singh (1 year ago)
Genes/alleles are not "heterozygote", it is called "heterzygous"
K King (1 year ago)
So helpful
awesome, helpful in higher education easily understable, it is permanently stored in mind
Navneet Abrol (1 year ago)
He just give introduction about eye colour nothing else but thanks for this information
AHD E (1 year ago)
theres not only blue and brown eyes there is also green
Omar Nahlawi (1 year ago)
test tmrw thnx it rlly helped!:)
Sophie Wysocki (1 year ago)
Still confused
Rashmi Keyal (1 year ago)
You guys are doing a great job Khan academy !!
Joseph ajrab (1 year ago)
0:27 he said Then if he were marry a brown HOT eyed girl ;)
YCRestEasyN (7 months ago)
Joseph ajrab someone knows his fetish
shinigami ryuk (1 year ago)
Is the dominant allele always represented by the capital letter?
2 Minute Classroom (1 year ago)
In dominant/recessive inheritance, that should always be the case. However, there are other types of inheritance that follow different rules.
Gerbie Gaming (1 year ago)
jiminie's kookie yes and recessive allele is represented by a lowercase letter :)
FrostySpade (1 year ago)
yellow looks ugly
Fiona Fernandes (1 year ago)
7:40 wanted to do that in blue .... does it in green...!!!???...
Michelle Rosas (1 year ago)
OMG thanks you teach better than my teacher, you should never stop making educational videos 😆
Dark Savior (1 year ago)
Khan Academy is the best! Thank you!
P
Princemharial Mejia (1 year ago)
thx we have a test tommorow we love you for teaching us
Prabhanshu Katiyar (2 years ago)
12:31 the standard convention is opposite
Prabhanshu Katiyar (2 years ago)
What causes green eyes then? He said that blue and brown are the only alleles
Echo.Jaxx (9 months ago)
Prabhanshu Katiyar eye color is an example of multiple alleles, so green eyes are caused by another variation of a character, which is a different allele. The example shown in the video is just a simple example of heredity.
Prabhanshu Katiyar (2 years ago)
ok
Frank Manning (2 years ago)
Prabhu - he said that he would keep the example simple by assuming blue and brown are the only eye colors. Maybe later on we'll deal with hazel, green, and black.
Yasmeen Khan (2 years ago)
This video is so great. Cleared so many of my doubts.
Rita Washington (2 years ago)
Confusing, looking elsewhere.....
1Future Dre (2 years ago)
Thanks to this video i finally understand Punnett Squares
Carolina B (2 years ago)
This is sooo confusing, I think you just confused more than I already was.
Carolina B (1 year ago)
+Prabhanshu Katiyar and you are?
Prabhanshu Katiyar (1 year ago)
then u better get a brain surgery done......
Harshil Nirmal (2 years ago)
What is F1 and F2 generations?
Tumbletastic 2 (2 years ago)
+A “the King in Copper” Hall its G1 and G2. At least in my school we go by G1 or G2.
King In Copper (2 years ago)
+Harshil Nirmal F1 is the generation from the first original pairing. F2 is a generation from the pairing of the F1 generation.
Maryam Jama (2 years ago)
Sometimes khan academy is confusing as hell.
Harley Hatcher (3 months ago)
yes sometimes it is confusing as hell all the time
Bright Star (3 months ago)
Maryam Jama They Lie.  See:  Pastor Dowell The Power of Worship.  See:  The island Hebrew. See: (BOSS CH 7 How to be Rich).
Kelsey B. (2 years ago)
Sorry, ur correct!
Kelsey B. (2 years ago)
At 13:02, you said the pair was homo, which is incorrect
Prabhanshu Katiyar (1 year ago)
He said homoLOGOUS, not honoZYGOTE... A homologous pair is a pair of chromosomes containing a maternal and paternal chromatid joined to together at the centromere. The have the exact same gene - although may have different alleles of these genes, Position (loci) and size. Members of a homologous pair pair up during meiosis.
Robyn (2 years ago)
+Kelsey B. if you're meaning when he said its a homologous pair...that term was correct. The parents are heterozygous instead of homozygous, but homologous means something else and it was used correctly here.
Tales Grimm (2 years ago)
At 9:37 the genotype had some trouble. Dominant always comes before recessive. Great work though!
Tales Grimm (2 years ago)
At 9:05 you said that brown eyes are recessive, other than that, this it great!
Wood Wanderer (2 years ago)
Test tommorow 😅 thx
mgallelli42 (5 months ago)
What'd you get on the test
BHAVIKA Gupta (11 months ago)
Wood Wanderer Same here😉😉😉😉
Cam Lee (2 years ago)
way to basic
Falcore75 (2 years ago)
+Virgil from hell too* I got you bro!
Philippe Neron (2 years ago)
Well done.
55
Jamal Zulfiqar (3 years ago)
this was a big help thanks!
Lena H (3 years ago)
+Codo Sacho Because brown eyed couples can have blue eyed children but blue eyed couples can't have brown eyed children, suggesting that if the brown eyed gene is carried it will be apparent.
Tales Grimm (2 years ago)
that was backwards
maekosin (3 years ago)
shorthand = a method of rapid writing by means of abbreviations and symbols, grid = grade, framework
Codo Sacho (3 years ago)
how do i know that brown is dominant and blue is recessive ?
Jon Hoekstra (2 years ago)
+Codo Sacho The only way to "know" this is to look at the result of a special kind of cross. You need to find an individual that you are sure is a heterozygote and see what that individual looks like. To make a heterozygote, you must cross a true breeding brown eyed person (from a population where ALL people have brown eyes going back many generations) with a true breeding blue eyed person (from a population that's strictly blue-eyed). Now you have an offspring you can be sure is heterozygous. Which parent does this hybrid look like? If it looks like one parent but not the other, that is the dominant trait. If the heterozygote has brown eyes, you label the brown allele dominant. All of the other proposed ways of knowing (what is more common, what the teacher says, which one has a capital letter) are incorrect or not very useful. An allele is dominant if it controls the appearance of heterozygotes.
Jos (2 years ago)
+BWOOD0419 THANKS XDXD
Jos (2 years ago)
+BWOOD0419 then please explain the question QAQ
IPMP (3 years ago)
+BWOOD0419 Dude there is no class named genetics class. Science or evolution maybe, but u don't sound qualified to be correcting people.
IPMP (3 years ago)
+BWOOD0419 how do u kno
D Man (3 years ago)
You spelled Mendel wrong you spelled it Mendl 
Sam Sheikh (3 years ago)
No. He's right, it's Mendel
Gizelle Blanc (3 years ago)
Taking the MCAT in 2017, I'm not even nervous anymore after watching a crap load of you guys videos. Thanks so much for this.
Michelle Santiago (3 months ago)
I'm taking in this September! Hope you do great
Sophie Wysocki (1 year ago)
How was it?
FrostySpade (1 year ago)
sammmeeeeeeee
Gizelle Blanc (2 years ago)
+YVNG NAMEK Sophomore
Kevin Kazi. (2 years ago)
+Gizelle Blanc U a freshman?
Fatimah Alfadeel (3 years ago)
Thank you
hira ashraf (3 years ago)
excellent explanation doc
Abol3z Rahmani (3 years ago)
IT WAS REALLY USEFUL , THANKS A LOT !! 
Park Paul (3 years ago)
THANK YOU
Abcd 1234 (3 years ago)
Plz tell me how u came to know that Brown eyes r dominant?
Jon Hoekstra (2 years ago)
+Abcd 1234 The only way to "know" this is to look at the result of a special kind of cross. You need to find an individual that you are sure is a heterozygote and see what that individual looks like. To make a heterozygote, you must cross a true breeding brown eyed person (from a population where ALL people have brown eyes going back many generations) with a true breeding blue eyed person (from a population that's strictly blue-eyed). Now you have an offspring you can be sure is heterozygous. Which parent does this hybrid look like? If it looks like one parent but not the other, that is the dominant trait. If the heterozygote has brown eyes, you label the brown allele dominant. All of the other proposed ways of knowing (what is more common, what the teacher says, which one has a capital letter) are incorrect or not very useful. An allele is dominant if it controls the appearance of heterozygotes.
Gizelle Blanc (3 years ago)
Its a darker eye color, darker colors are more dominant.
Truth Seeker (3 years ago)
YOU ARE AWESOME .. how did you know all these information :D you're teaching math physics biology and even economy !! are you even human ?!
Chaos Zombie999 (2 years ago)
+Abdulrahman Mahdaly he knows stuff yew
Tina T (3 years ago)
The mother had Red eyes are (RR) but the dad had green is (rr) but what with the outcome be red or green?
Prabhanshu Katiyar (2 years ago)
Hey who has red eyes????
spartankingnoble (3 years ago)
Red Eyes are dominant? 
Tejas Sub (3 years ago)
all heterozygous Rr... phenotype red for all
celestial hunty (3 years ago)
THANK YOU SO MUCH
Nobody - I'm an artist (3 years ago)
Dear Khan, I absolutely adore your free education but strongly feel you earn some compensation! If you would release your lessons on DVD for example I would buy them in an instance, and I know I'm not the only one! PLEASE
Classroom (2 years ago)
+We Are Anonymous why not donate it now please
Tales Grimm (2 years ago)
Nobody watches DVD's anymore, he should have a V.I.P. section of his app developed.
Abhishek Ravindra (2 years ago)
Yeah most of the Indians are face this problem of better bandwidth. Sal can sell these videos in blu-ray all thousands of videos and just one disc and I know everyone will definitely buy.
Cheaper (2 years ago)
+the brony gam3r Khan is also his last name.
+rainah k his name is sal not khan, khan i=academy is the website
WakeUp (3 years ago)
So Gene is on the locust? I'm just kidding :) - hey that makes a good mnemonic! 
ItzKhateebYT Minecraft (3 years ago)
Thank you :-)
jacobmufasa (3 years ago)
thank you so much.
Crazee Puffs (3 years ago)
And u speak to fast xD
Crazee Puffs (3 years ago)
Its supposed to be Gregor Mendel :D
Alan Outram (4 years ago)
a priest that would mess around with plants......where it all started going wrong.
Hailey Reynolds (1 month ago)
a monk* not to be rude... lol
Sam Sheikh (3 years ago)
Omfgggg.
yung clout god (3 years ago)
lol...
zenoch burt (4 years ago)
what about hazel eyes? I have hazel eyes, how can that happened? Would it come form my grandparents because my dad and mom both have brown eyes same with my sisters. Dose it mean I have differ genes?
Draken Kartikay Kaul (4 years ago)
Can you tell me the difference between traits and alleles. In our biology classes, we don't use the word alleles we use the word traits. For example, blue eye trait.
chinmia (4 years ago)
Alleles are variations of a trait. Eye color is a trait, but each allele represents a variation of that trait. Different variations, or alleles, for eye color are brown, green, blue, hazel, and so on. Each person has two alleles for each trait - one from mom and one from dad. That's what the B and b represent...one allele from each parent. Now, some alleles are "stronger" than others - the dominant ones. Dominant is represented by 'B' and recessive is represented by the lowercase 'b'. All dominant means is that all it takes is one allele to see that trait. So, if brown eyes is B and green is b, all you need is one B from either parent to have brown eyes. If you get two recessive alleles (bb), you end up with green eyes. I know that's a lot of info. I work in genetics, so I try not to sound too confusing. If you have anymore questions or something's unclear, feel free to ask.    
Draken Kartikay Kaul (4 years ago)
Okay! Thanks!
Undeaddude43 (4 years ago)
The Alleles make up the trait, for example for the "blue eye" trait contains the alleles Bb if it were heterozygous, or containing two different alleles. The two alleles are B and b which make up the blue eye trait
Patrick McGavin (4 years ago)
yeah I like these episodes, I'm on the final season
sagellivokin (4 years ago)
Khan, I love your videos. I've been watching your Biology playlist non-stop and I'm getting really excited about Biology. Your video on meiosis got me hooked. Keep up the good work!
Shane OShea (4 years ago)
+epicchan1668 Salman Khan...
sagellivokin (4 years ago)
+epicchan1668 haha I was writing to the channel itself.
epicchan1668 (4 years ago)
His name is Sal.
Andre Olatunbosun (4 years ago)
Great video
Helmi Jaber (4 years ago)
thank you ,thank you ,thank you ,I finally understand now
Daniel Mazur (4 years ago)
Very helpful
Janis S Kyzer (4 years ago)
I love your drawings and some of the explanation's, but I feel you can shorter videos, by not repeating the same thing or going off on tangents
Kellie D (4 years ago)
This video and another has helped so much prepare me for a quiz tomorrow! thank you!
paynostagram (4 years ago)
having a marathon of your bio videos before my sat 2 in a month thanks!! 
Vako Abesadze (4 years ago)
thank you so much but you said tooth sizes also, so i thought it would be dihybrid crossing. i needed dihybrid crossing but thank you very muck :))
In reality eye color is not one gene classical Mendelian inheritance trait. This trait influenced by many genes. But for exampe it is OK.
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PolkaDotSunshine9 (4 years ago)
This helped me so much. thank you sir
GamingNinja07 (4 years ago)
thank you! i finally understand!
Leighvern Chadwick (4 years ago)
What does nerfighteria mean?
LadyHelena Ravenclaw (4 years ago)
I love you so much wow
OrAngeAnArchy (4 years ago)
thank you CGP Hank!
cweesta (4 years ago)
Wish this went into detail about codominance, incomplete dominance, etc or that there was another video for more depth. But as always, awesome job!

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