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3.5.7.1. Family Trees 2

More genetics problems with family trees solved. (Page 28)

Genetics problem 207

The figure indicates the transmission of a certain phenotype (individuals in black) in a family (men are represented by a square and women by a circle).

a)  Indicate if this phenotype is dominant or recessive. Give reasons for the  answer.
b)  Indicate if the gene that determines this trait is  autosomal or  is linked to sex. Give reasons for the answer.
c)  List the possible genotypes of all  individuals. Use the letter A (uppercase) for the dominant allele and the  letter a ( lowercase)  for  the recessive.

Genetics problem 208

The figure indicates the transmission of a monogenic trait in a family (men are represented by a square and women by a circle). The character has two alternatives indicated in black and white.

a) Indicate whether the allele that determines the alternative represented in black is dominant or recessive. Give reasons for the answer.

b) From the genealogy data it can be concluded that the trait is autosomal. List the possible genotypes of all individuals. Use the letter A (uppercase) for the dominant allele and the letter a (lowercase) for the recessive.

c) Give a reason why it can be concluded that the trait is autosomal and not sex-linked.

Genetics problem 209

The figure indicates the transmission of a monogenic trait (individuals in black) in a family (men are represented by a square and women by a circle).

a) Is it a dominant or recessive character? Give reasons for the answer.

b) Indicate the most probable genotype of each of the individuals. Use the letter A (uppercase) for the dominant allele and the letter a (lowercase) for the recessive.

c) Is the gene that determines this trait autosomal or is it located on the X chromosome? Give reasons for the answer.

Genetics problem 210

The figure indicates the transmission of a certain phenotype (individuals in black) in a family (men are represented by a square and women by a circle). Character determination is monogenic.

a) Is the alternative that appears in black dominant or recessive? Give reasons for the answer.

b) Indicate the most probable genotype of each of the individuals. Use the letter A (uppercase) for the dominant allele and the letter a (lowercase) for the recessive one.

c) Is the gene that determines this trait autosomal or is it located on the X chromosome? Reason the answer.

Genetics problem 211

The figure indicates the transmission of a certain phenotype (individuals in black) in a family (men are represented by a square and women by a circle).

a) Indicate if this phenotype is dominant or recessive. Give reasons for the answer.

b) Indicate if the gene that determines this trait is autosomal or is linked to sex. Give reasons for the answer.

c) List the possible genotypes of all individuals. Use the letter A (uppercase) for the dominant allele and the letter a (lowercase) for the recessive.

Genetics problem 212

The figure indicates the transmission of a character in a family (men are represented by a square and women by a circle). The character has two alternatives indicated in black and white. This trait is known to be determined by a single sex-linked gene (located on the X chromosome).

a) Indicate whether the allele that determines the alternative represented in black is dominant or recessive. Give reasons for the answer.

b) List the possible genotypes of all individuals. Use the letter A (uppercase) for the dominant allele and the letter a (lowercase) for the recessive one.

c) Indicate the probability that the couple indicated with an arrow has a descendant with this phenotype: (1) if it is a boy; (2) if it is a girl.

Genetics problem 213

The figure indicates the transmission of a character in a family (men are represented by a square and women by a circle). The character has two alternatives indicated in black and white. This trait is known to be determined by a single sex-linked gene (located on the X chromosome).

a) Indicate whether the allele that determines the alternative represented in black is dominant or recessive. Give reasons for the answer.

b) List the possible genotypes of all individuals. Use the letter A (uppercase) for the dominant allele and the letter a (lowercase) for the recessive.

c) Indicate the probability that the couple indicated with an arrow has a descendant with this phenotype: (1) if it is a boy; (2) if it is a girl.

Genetics problem 214

The figure indicates the transmission of a certain phenotype (individuals in black) in a family (men are represented by a square and women by a circle).

a) Indicate if this phenotype is dominant or recessive. Give reasons for the answer.

b) Indicate if the gene that determines this trait is autosomal or is linked to sex. Give reasons for the answer.

c) List the possible genotypes of all individuals. Use the letter A (uppercase) for the dominant allele and the letter a (lowercase) for the recessive.

Genetics problem 215

After studying the transmission of a certain pathological phenotypic character in a family, the result that appears in Figure 1 has been obtained, in which the individuals that manifest the characteristic appear shaded. In view of the data, reasonably indicate which type of transmission is most likely the character under study.

Genetics problem 216

In the diagram of fig. 3 represents the transmission of a certain pathological character in a family. Considering those represented in white as healthy individuals, what type of transmission does the process under study follow? Reason for the answer and indicate accordingly the genotypes of the individuals indicated with the letters.