Tag: inherited changes

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Questions Related to inherited changes

Multiple choice biology inherited changes linkage and crossing over linkage and recombination genetics: inheritance

A human male is heterozygous for two autosomal genes A & B and homozygous dominant for 3rd autosomal gene C. The individual is having sry gene (S) on its Y-chromosome. What will be the probability of sperms to carry abcS condition? 

  1. $\frac{1}{4}$
  2. $\frac{1}{8}$
  3. $0$
  4. $\frac{1}{16}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The human male is heterozygous for A and B, and homozygous dominant for C, with genotype Aa Bb CC S (plus Y). To produce a sperm carrying the abcS condition, the sperm must receive recessive alleles a and b, but the individual is homozygous dominant for C (meaning only allele C is present, never c). Therefore, the probability of producing a sperm with the allele c is 0, making the overall probability 0.

Multiple choice biology inherited changes linkage and crossing over linkage and recombination genetics: inheritance

Assume that the occurrence of nitrogen bases in adjacent positions in a DNA strand is random. Identify the minimum number of nucleotides in a DNA strand where GAAT can occur once on the basis of probability

  1. 512

  2. 256

  3. 4096

  4. 1024
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The probability of a specific 4-nucleotide sequence occurring at any position is (1/4)^4 = 1/256. To expect this sequence to occur once, you need 256 positions. Thus, 256 nucleotides are required.

Multiple choice biology inherited changes linkage and crossing over linkage and recombination genetics: inheritance

In an organism punk is a sex-linked recessive trait and black hair heterozygous female is mated to white male which is not spotted, the phenotypic ratio of the offspring would be :

  1. 1/4 spotted black; 1/4 pink spotted white; 1/4 unspotted black; 1/4 uspotted white

  2. 1/2 spotted black; 1/2 pink spotted white

  3. 3/4 pink spotted black; 1/4 pink spotted white

  4. 3/4 unspotted black; 1/4 pink spotted white
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice biology inherited changes linkage and crossing over linkage and recombination genetics: inheritance

A man with pure blue eyes and pure black hair marries a woman with black eyes and red hair. (Black eyes are dominant over blue eyes and black hair over red hair). What will be the probabilities of phenotypes of the children?

  1. $50$% with black eyes and black hair, and $50$% blue eyes and black hair

  2. All will be with black eyes and black hair

  3. Both the above cases are possible
  4. $1 : 1 : 1 : 1$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Man is bbhh (blue eyes, red hair - both recessive). Woman is BBrr (black eyes dominant, red hair recessive). Their F1 progeny will all be Bbrr (black eyes, red hair). When crossed with bbhh, all offspring will be Bbrr (black eyes, red hair) in phenotype. However, the question structure suggests the man is bbhh and woman is BBHh, giving 50% black eyes with black hair and 50% blue eyes with black hair.