Hi welcome all friends this is your anatomy guru as we all know that in all medical and PG entrance exams and also in OSPI held in various medical colleges in India we get less than a minute to solve a question so time conservation is very important in these exams therefore in this video we would discuss How to solve a pedigree chart in less than 30 seconds? Step number 1. First we have to find that the inheritance pattern given in the question is a dominant or recessive. For this we have to know one simple idea that is is keeping present or not. Look into these two simple pedigree charts.
Is the first generation second generation and third generation. In the first all the three generations are affected in a continuous sequence. So no skipping is seen.
This pattern is known as a dominant pattern. In the second one, the first generation is affected, the second generation is not affected but the third generation is affected. So the second generation shows a skipping pattern. This type of inheritance is called as a recessive pattern. Step number two.
Now we have to differentiate between an autosomal pattern and a sex ring inheritance. For this we have to look into what is known as man to man transmission or father to son transmission. Now look into this particular picture.
Females are also affected and males are also affected. In second generation we can see a father is transmitting its state to his son. So this type of pattern is seen in an autosomal inheritance. Next step is to find out a Y-linked inheritance. For this the golden rule is only males are affected.
For example look into this pedigree chart. Here all males are affected also there is no skipping of generation no skipping of generation therefore this type of inheritance is a vialing inheritance step number four would be to look out for any mitochondrial inheritance for this the golden rule which we will follow is that It is inherited from mother only. For example, look into this pedigree chart. Here, the mother is transmitting its trade to all its daughter and sons. Also, here also, the mother is transmitting its trade to all its daughter and sons.
But here, the father is not transmitting. it states to its daughter or son. Therefore it is a maternally inherited inheritance which is known as mitochondrial inheritance.
Now we should look into some practice exercise. In this pedigree chart we can see every generation is every generation no skipping thing therefore it is a dominant pattern Also we can see male to male transmission. Therefore it is also an autosomal disorder. Therefore in total it is an autosomal dominant inheritance.
In this example no skipping is seen. Every generation is affected. so this is a dominant pattern of an identity next in this the father is transmitting its states to all its daughter all his daughter but not to his son but not to his son here also you can see father is transmitting to his daughter but not to it here also you can see father transmitting to its daughter but not it so This pattern is always an X-Ling dominant pattern.
So remember for X-Ling dominant if father is transmitting to his daughter but not to his son then it is an X-Ling dominant pattern of anatomy. In this example we can see that the female is transmitting its trait to all its daughters and sons. Here also we can see the female transmitting to all its daughters and sons.
Here also the female transmitting all its trait to its sons. But when the male is affected, he is not transferring any traits to his daughters and sons. Therefore, this inheritance is a mitochondrial inheritance. Next in this pedigree chart we can see not all generations are affected therefore skipping is seen So this is an recessive inheritance Also, we can see male to male transmission therefore altogether this is an autosomal recessive inheritance look into this example here skipping of generation is seen Therefore, it is a recessive inheritance. But no male to male transmission is seen.
So it can be an autosomal recessive or an autoexceling recessive inheritance. But here you can also see that males are affected, females are not affected. So this goes more in favor of exelin recessive inheritance as compared to autosomal recessive inheritance where males and females are equally affected.
So, If such question arises in exam then we can easily differentiate between an extreme recessive and autosomal recessive by looking at which category or which gender is more effective. If males are more effective as compared to female it is an extreme recessive disorder. If they are both equally effective males or females then it is an autosomal recessive disorder. Also in this pedigree chart we can see there is skipping out generation therefore it is a recessive inheritance here no male to male transmission is there no male to male transmission is there therefore it can be an autosomal recessive or an X-ring recessive inheritance but here we can see females are also affected and males are also affected so this goes more in favor of autosomal recessive disorder as compared to X-ring recessive rate.
In this particular chart we can see that there is skipping of generation therefore it is a recessive disorder also no male to male transmission is there therefore it could be an autosomal recessive or axon recessive but females and males are both equally affected therefore it is an autosomal recessive disorder. In this particular chart you can see all generations are affected Also male to male transmission is there. Therefore it is an autosomal dominant disorder. In this also we can see no skipping.
We can't see any skipping all generation are affected. Therefore this is a dominant disorder. Also males are transmitting to its daughter but not to its son. Males are transmitting to its daughter but not to its son. sons therefore it is an X-linked dominant disorder.
In this pedigree chart we can see there is skipping of generation therefore it is a recessive no male to male transmission is there therefore it can be an X-linked recessive or an autosomal recessive but here males are more affected as compared to females therefore it is an X-linked recessive disorder. In this last pedigree chart we can see that all the males are affected all the males are affected but we can't see any skipping all generations are affected therefore it is a violent inheritance hi all friends this is Dr. Santh now you are Anatomy Guru thank you for watching this video if you want more of these videos which would help you to save to the subject of anatomy Join my Facebook page or comment below and suggest some topics which are nightmare for you. Also, if you like this video, please share, like and subscribe this video and share more with your friends. Bye.